Suggest Treatment For Nausea, Abdominal Cramps And Headache

Hello, I m having trouble figuring out if I m pregnant. I took this Depo shot in August and in October I was supposed to get the shot again but I didn t . A week later of me not getting the shot I had unprotected sex. And about two weeks later my period came on , it s been on for about seven days , but I m experiencing nausea , cramps, and headaches, and I ve also thrown up. I ve taken pregnancy test and there all negative , but I normally don t vomit during my cycle, could you help me with what this might be