I had my last period around first week of February, then I had my first experiencing engaging in sex last February 18 after a drinking party( it was not that rough and we had just 1 round, my partner told me he withdraw his penis when he was about to cum) the next day I felt that my abdomen bloated and starting to feel abdominal cramping, I was paranoid thinking I might be pregnant so I did several pregnancy tests from Feb 20-Feb 25 then I drank emergency pills. Then last February 27 I took the serum pregnancy test with a negative result. I am having constipation and lower back pain and still bloated stmach with feeling of acid inside for almost 2 weeks now. Help!! what does this mean ???