I was sexually active last night and the man was not wearing protection. I was not aware that he was going to try to have intercourse so when I realized what was happening I stopped so he did not ejaculate but he did get inside of me. I have my period every two weeks and I am supposed to get my period tomorrow, which I believe means that I would be ovulating either yesterday or today. There was foreplay leading up to this so I am scared that I may become pregnant from the sperm in pre-ejaculate . Do you have any suggestions to what I should do? Also, I am considering taking the morning after pill or plan B; but I have heard it is terrible for you from some non reliable sources. So if I do decide to take it can you tell me what the side affects are and if it is indeed really bad for you to take?