Consider how you are wearing clothes when you have to go outside or if your house is very cold! An experienced mountaineer said that clothes are the mediator between being dead and being comfortable. One of my favorite mountain layering systems is that of Colin Haley, a professional alpine climber who has been to extremely cold places. ( Described here https://www.patagonia.com/stories/colin-haleys-clothing-system-for-alpine-climbing-in-the-chalten-massif/story-95145.html). I also reccomend reading about the military (fuck da troops) PCU system (https://www.itstactical.com/gearcom/apparel/comprehensive-guide-protective-combat-uniform/). I also use the recently understood vapor barrier liner as explained by Andrew Skurka to trap in more heat (https://andrewskurka.com/vapor-barrier-liners-theory-application/).

For your inner layer, choose a pair of long underwear shirt and pants that are able to wick away moisture. If you have something that is not cotton to wear as your inner layer, you should use that. If you need to, you can wear a short sleeve athletic shirt and moisture wicking underwear and then a pair of long underwear on top of that to add more warmth with less bulk.

If you have fleecy pajamas or sweatpants and a sweat shirt of some kind, choose that as your middle layer. I tend to veer away from typical advice here for such cold weather, as does Colin Haley: I wear a very tightly woven windbreaker pants and wind-shirt that traps in sweat to trap sweat and create a micro-climate around my body. This reportedly allows a 300% increase in heat trapped next to the body, and I have definitely noticed this. I also do this with my feet by wearing a moisture wicking sock (I like using thin synthetic or wool dress socks for this), some small trash bags above that, and then a warm pair of socks (I like wool work socks for this). You can take off the trash bags when you head to bed because if you leave them on you may get macerated skin on your feet, which is painful. If you don't have a windshirt or windbreaker pants, any very tightly woven fabric will work.

Shoes are very important, but I tend to avoid a waterproof shoe because waterproof shoes don't dry out very fast. If you have a shoe made of leather or synthetic with a good rubber sole that has a lot of tread on it that should be your outside shoe. if you have slippers with a fleecy lining or other warm layer inside then you can wear those indoors. I make an exception for rubber boots, though as those can be useful if you have a lot of slush on the ground.

Next, you should try wearing any kind of insulated layer you may have over the wind-shirt and your mid-layers. If you don't have an actual insulated jacket, you can try wearing more pajamas on top of everything else as your insulation layer. You should wear your tightly woven pants over your insulation pants because the tight weave will help protect the insulation on your legs from the outside world.

For your head, have some kind of warm face covering such as a balaclava or scarf that can cover your face, neck, and lower part of your ears, I pair this with a fleece hat in order to double up my insulation and often choose a hooded layer to keep my head even warmer and protected from wind. I find that if you have glasses or goggles, these are also very helpful in protecting your eyes from the wind. If you have sunglasses, that is even better because they can ward off snow-blindness.

For your hands, you don't need very expensive things like fancy insulated gloves. Go to your local hardware store or sports supply store and find a good pair of insulated rubber gloves or insulated leather gloves. My personal preference is the rubber gloves. When I wear those, I usually use a pair of good liner gloves and then the rubber gloves on top of everything. However, this is because dexterity is a concern for me. If only warmth is necessary, you can buy either a pair of lined mittens. If you think it is necessary, try getting both gloves and mittens and sizing your mittens up to be worn over every other pair of gloves you have. (Here is the system I use: Showa TemRes 282 rubber gloves over a thermax liner glove with a pair of the cheapest lined mittens I can find or even a pair of warm socks over everything. Don't wear too many gloves or too many socks, because that will make your hands and feet colder!). Always have multiples of everything you are using to cover your extremities because these things will get wet one way or another.

Avoid wearing cotton whenever possible, because it does not dry out when it becomes wet with sweat. Avoid fancy waterproof fabrics as your outer layer, because they may keep you dry from the rain but they will block out the transfer of water from your body to the outside world despite some claiming to be breathable. Rather than attempting to stay dry, attempt to dry out fast.

When you go to bed, have a water bottle that you have filled with a hot liquid in the space where you will be sleeping, and perhaps consider using a trash bag or emergency Mylar blanket to act as a vapor barrier liner over a "cocoon" of your comfier thin sheets to wear against your skin. For your thin sheet, I highly recommend a fleece blanket as opposed to a cotton blanket. On top of that, have your warm insulated sheets. Pay attention to what is beneath you. If you don't have a proper bed to sleep on, pile anything you can find that can form a barrier between your body and the ground beneath you because the ground will sap away your body heat and make you cold. Cardboard, piles of newspaper, anything that can insulate you from the ground is essential to staying warm. Sleep in your layers to increase your warmth. To keep whatever you have as insulation dry and protected in this scenario, use a second trash bag to act as a makeshift bivy bag over everything else. You can cut a hole into a trash bag to put over your head as a sort of protective hood. As others have said, try making the space that you have to warm up smaller, such as by sleeping in a tent indoors if you can. You can also string up sheets and towels around your sleeping space in order to create a micro climate around your sleeping area. Sleep with another person if possible in order to make sure their body heat is added to your sleeping space.

If your gas lines are no longer working you can make a stove to cook and boil water with using only a soda can, some denatured alcohol, and some basic tools (Shown here: https://www.youtube.com/watch?v=OvvdLVUJXZc). For fuel, you can use HEET or isopropyl alcohol. When you have the fuel, put it into a bottle that is clearly marked as your fuel bottle and keep it close to your body under your insulation in order to keep it warm enough to use. For water, get some snow and use any water you have on hand to put the snow into so it can melt faster. Boil your water to sterilize it before using it to make food or to drink. You can make a cooking pot stand out of a thick wire coat hanger if you have one or any kind of metal that you can bend into the right shape. To make your stove more fuel effecient, try putting a cut up cookie sheet around it so that the heat from the stove reflects back to your cooking pot.

If it needs to be warm or it needs to be dry, rely on your body heat and keep it under your insulation layers next to your body or in the space where you will be sleeping.