I worry a lot, and I know I'm probably over thinking this whole situation. So here it is, I had sex in November on the last day of my period, however the condom slipped, this was before he ejaculated, but I have read online that pre ejaculate can still cause pregnancy. My 'period' then came 9 days early and was very light, I read that this could be implantation bleeding so I did a pregnancy test 22 days after I had sex and it was negative. I've had periods that are heavy which is normal for me ever since this, however I've heard some women still get periods whilst they're pregnant! Help!