>>2263005OP just for an understanding of what you are working with for the intent of the thread. What tools do you have access to? Like a multitool or pliers etc... Are things like glass jars with metal lids around for you to make oil candles with safely? Could you get some form of exhaust duct, tech screws, or a carbon monoxide detector? Things like that. Have you considered doing something like an indoor tent set up to conserve heat? I want to help, but telling you about stuff you can't do or get is a big waste of everyone's time and energy.
If you have a room in the building you feel safe in and if it has enough room. If you can get a small cheap tent put it up in there with your bedding inside. It will trap all of the heat you make in a much smaller space and stay warmer. If you want I can try and emulate your set up and try and find some thrifty ideas to make it warmer safely. I looked online and Walmart (I know sorry) claims to have small pop up tents available. Those are the easiest to set up. No tools or janky poles to put together. It fits your must be portable and easy criteria. If you can get some cheap blankets to drape over it you should be able to keep a good deal of heat in it for little money or work.
https://www.youtube.com/watch?v=BUIhCCq3zqghttps://www.youtube.com/watch?v=ysw6CEbSiakMaybe someday you can do something like this guy.
https://www.youtube.com/watch?v=lSt96KFFHxA 