am I pregnant or am I just fat?

First of all I dont have regular periods. about two months ago I bleed more than you would with a period I went to the doctor and first he told me it looked like a miscarriage than he turned around and said it was a period. than just last month I think I had a period but it was a brownish pinkish color after that happened I gained alot of weight to the point none of my pants fit me anymore and if I wear even a loose shirt you can see my stomach poking out. ive been very tired even when I just wake up I feel so drained, my boyfriends even told me ive got more moody worse than I usaully am, I dont know if its just me or if I go to the bathroom alot more lately, I know ive been eating alot more ive been wanting hamburgers here lately. but I think my bodys just lacking something. I have been very nauses I dont throw up but it comes up and I swallow it ((I know its nasty but I hate throwing up)) Im so confused everybody in my family said I have gained weight if I was pregnant or just getting fat :( please help me I dont want to think im pregnant and than be disappointed that im not!!!???