What could be wrong ?

Well for like two months I have been trying to get pregnant but it didn't happen. (Just got off depo shot) in Feb . So anyway I gave up and just said forget it. Me and my guy I been having sex with has been having a lot of unprotected sex . And on March 29,2016 I had sex but I bleed a little very light and the blood was bright red. Anyway that was it .. Then this month I had been feeling really weird like I would eat but after I eat it feel like I gotta throw up( which been happening for months now) then I have a taste for something then as soon as I get it I eat it and then I feel sick. It's certain stuff that I like but can't eat bc it's nasty at that moment. Then it's like I'm hungry but can't eat and wen I do eat an hour later I'm back feeling like I ain't eat at all. Now I'm cramping I think I'm not sure. But my stomach is hurting really bad . Then yesterday I drink some water and juice earlier that day then later I had to use the bathroom like really bad after I just used it.