Is this normal, im 16 yr old girl and i think i have a medical problem?

well i have not been in good health for a while. I used to have horrible sleeping problems but now its better kind of. I have stomach pain. I get sick easily and its hard for me to recover. Im constantly freezing regardless of weather. I have the need to throw up, but i never do. I have head aches. I have never had an affinity for meat, although I do eat rice and beans so i think im getting the proper protein. Also it might be stress related im president of too many things at my school at ap classes.. and finals. I have had this problem for three years now. Could this be to my food choice or stress? I am 5' 6 and 113 pounds. please help me.