I had my period around January 17. On January 30, I hooked up with a boy. We did not have sex, but there is a chance that semen got near my vagina or pushed in by fingers. I was very drunk, but since I have never had intercourse, I was told that I would probably be able to tell. I took Plan B about 12 hours later just to be safe. After a nerve wracking week, on February 4 I got a heavy flow that lasted as long as a period. I thought all was well. I have not had any type of physical intimacy since then. On March 9, I had still not gotten my second period and was not too nervous because I am not very regular. However, I started to get dizzy and light headed. I took a pregnancy test and it came back negative. On March 14 I started getting a very light blood flow that was alternately light pink and dark brown. I barely needed to use a tampon. I was nervous again, so I took two pregnancy tests, one on March 25 and the other on March 26 in the morning and both came up negative. In the past two days, my breasts have been a bit sore, but nothing too crazy, and I have continued to feel a bit lightheaded, nothing like before, and nauseous, but I did not lose my appetite or have any food aversions. Should I still be worried that I am pregnant?