At least your heat went out before the middle of the cold winter but I know it's not enjoyable not having heat. I've had a couple mornings of 32° and the heat hasn't been turned on yet in my apartment building so I layer on clothing in the morning till the sun has warmed up my apartment.

I hope you're doing better and maybe instead of trying to get up and sitting for long periods of time, try getting up more often for short periods of time.