I had unprotected sex (first time, spur of the moment, I know I was stupid) exactly 4 weeks ago to the day, halfway through my cycle. The next day, I went and got plan B and took it 20 hours after the sex. I also started taking Marvelon 28 on the following Sunday. We have had a few accidents with condoms since then (slipping off). I have been on the sugar pills for 4 days, and last night we were rather.... vigorous. I had been suspecting I might be pregnant as well (sore breasts mostly) so I took a test right after getting busy (negative). I started to bleed lightly after sex, and have been bleeding lightly on and off since then. Normally my period is really heavy and makes me throw up several times, so I'm a bit freaked out. I took the second test this morning, negative again. Am I pregnant, or just having a weird period because it's my first month on the pill?