Me and my girlfriend had sex in march, but I'm not sure what day. Well a few days later she started her period and she was supposed to. She was supposed to start her period on April 1, but she still hasn't started and now it is april 10 and she still hasn't started. She took a pregnancy test today and it said that she isn't pregnat. I really want to know what is going on because I am so scared. Please help.