All right, I have been on birth control pills for almost 3 years. About 6 months ago I switched birth control. Everything has been fine up until the last couple months. I got really sick, in 2 weeks I had 2 cases of the 24 hour flu, a bad cold, and got strep. I was put on antibiotic. I wasn't told until I was done with it that it makes birth control ineffective or less effective. Ok, so that was November. I got my period, it was a couple days later than usual but I still got it. All was normal. Well now, I'm having some pregnancy symptoms. I'm having tender breasts, headaches, backaches, dizziness, cramping, and some nausea not enough to make me sick though. I haven't thought too much about it until today when I started bleeding. It's not a normal blood, it's not as heavy as normal periods, and it's really brown. The weirdest part is, I am not supposed to get my period for another 10 days. I have never had an early period with birth control or before I was on birth control. I've always had a pretty normal cycle. I figure I will take a pregnancy test after I'm supposed to get my period, I just wanted to see what you thought. Could I be pregnant and be having implantation bleeding?

This very well could be break through bleeding because of the antibiotics. Yes, antibiotics do in fact make the pill much less effective.

Implantation bleeding is not proven. Usually women who have "implantation bleeding" become pregnant right before their period and the hCG hormone is not strong enough to stop the bleeding completely. So, please don't think that you bleed because an ovum is implanting, that's just not so.

You can try to test next week, if you feel you are pregnant. But remember that pregnancy symptoms and premenstrual symptoms are very much alike.