Hi i am 18. I had intercourse on the 21st, and 25th of November and on the 5th of December. I did take a plan B on the 21st. It is now February. In December i started getting tiny bumps on my nipples and my nipples itched. They no longer itch. I also have been having headaches.I have not missed a period but my period in January was only 4 days.(which is weird since my periods usually last a week and two days) My period was heavy on the first day and very light on the other days. Recently I have been cramping for two weeks now with light green/ yellow discharge and stains in underwear. I don't think I'm ovulating because I don't have clear stretchy discharge. My period isn't suppose to come until the middle of February. I did take a pregnancy test a week ago that said negative. Could I possibly be pregnant? I'm scared..