Had unprotected sex with my boyfriend right after my period in the beginning of February (probably around feb 3-5) , he ejaculated inside and a day later I took plan B. A week later after taking the pill, I got weird brown spottings, which went on for a few days on/off again, then I started bleeding a little (withdrawal bleeding) and that stopped about two weeks ago. I got a home pregnancy test (one of the cheap ones so I'm not sure how accurate they are) and it showed negative. This was a week ago (March 2nd) and it's already March 7th, I still haven't gotten my period and have been pretty nauseous for the past week.. Is this a side effect of the pill or This could be pregnancy? Help?