Stomach and back pain on my left side?

hello will just give you a bit of backgrounc, my real question is does anyone know what i can eat that wont make me throw up again?, but i went to the hospital last night with really bad pain in my left lower stomach and back, and they did a blood test and gave me.. i think it was panadeine forte... which didnt do anything, and then a painkiller that went up my nose (eeeew) that helped a little, and after that i was able to move my legs and sit up again. before i went to thhe hospital i was vomiting really violently, never had naything like that before,like that bad, but after a couple hours they needed more beds and i said i was good to go home because it only hurt a little after the nose painkiller thing.... so anyway... i was sick again at the hospital, then again when i got home, and thought id be able to sleep it off but after bout an hour of sleep i woke up again and the pain is back, all down the left side of my stomach, and and back, i cant move my leg on the left side, and its spreading across to the tops of my thighs on both sides.... they didnt tell me much at the hospital which is cool cos they were busy as hell, but does anyone know what this could be? i think im going to go to the docs when it opens bcos the pain is so bad now that i had to i crawl to the computer and take breaks to just lie on the floor cos it felt cold... lol... i have chills as well that are just... making my whole body shake and i cantcontrol them and i feel like im a hundred degreees, im so hot and cant cool down.... also, does anyone know what i can eat that wont make me sick again? something harmless like celery or cuber? i think being hungry is adding to the stomach ache i havnt eaten for 2 days, just cos i couldnt keep anything down..... im 18 years old, if that helps, so i dont think its my kidneys or anything..? jst no idea lol never felt pain like this before, apreaciate any help sorry for spelling