So I've been having lower back pain on and off for a few years, and figuring it was normal I wrote it off as a consequence of A: being fat and B: exercising to lose said fat. The problem with my theory is that my back started hurting more after I dropped from 350 to 200 instead of less, preventing me from doing my daily five-mile walk or doing much exercising in general and, combined with the stress of college, causing me to go back up to 250. Well, OK, I thought, I can handle that, at least it's not hurting really bad. So over the past year it's gotten worse, and finally, today, I wake up crying and needing to vomit after only four hours of sleep because I'm in so much pain that I can't get up, and no matter how I try to turn or position myself nothing stops it. Eventually I managed to make it to the living room and spend some time sitting with my back on a heating pad, which (barely) relieved the pain while I was there but now that I'm back in my computer chair it's come back full force. I have aspirin allergies and most pain medication causes me to vomit, so any medicine taken orally is right out. I'm pretty broke, so my means to handle this problem is limited, and I mean 'let's assume this is after the apocalypse and there's no doctors or chiropractors or anything' sort of limited.
Does anybody have any sort of advice for this situation?