I had sex with my boyfriend on Saturday, but I took my birth control pill two hours later than usual. I started what I think is my period on time on Wednesday, but it started off brown and light. After a few hours it went to normal flow, then it was light again. I was worried and wanted to see if it was really my period, so I took the tampon out and needless to say I bled all over my panties and on my legs. I was relieved thinking it was my period, but after awhile it stopped and lightened up again. This has never happened before, usually I have a really heavy flow and it doesn't start getting light until later... Could I be pregnant? Even though I started this 5 days after the intercourse and on time my period's schedule (because of the birth control)?