unprotected sex while on birthcontrol

I had unprotected sex in May so about a month in a half ago and literally right after we got done he said " I'm taking you to the store before I take you home ( he's a booty call ) and he bought me it and it conceded me cause I was like um okay? Sure. But anyways the moral of the story is it's been a month an 5 days maybe since I had my period I was really really worried cause I always get my period in the middle of the month and I always know when I'm gonna get it I get a feeling like I think I'm going to start and I'm 95% right but I didn't get that feeling at all last month I was like what is going on? Maybe it's the pill and I waited and waited and that whole month went by and still NO period so I went and bought a test it was negative thank God!. i started having light pain in my stomach sometimes it be a really sharp pain on my sides I can't remember which side I thought it was nothing but today (July 3rd ) I had really really bad cramps like I was on my period so I went to the bathroom it was light blood and I put a tampon and went back to the bathroom 2 hours later to change it and it wasn't even how my period usually is it was light blood. So I put a new one in and I put it in around 4 or 5 and got off work around 12 am So I went at least 7hours without changing it and it still wasn't barley anything so I didn't even put one in when I got home causes it's not even enough To wear a tampon and I'm just curious to why my "period" is doing that??