So I'm 18 and my last period was July 21st, if I am pregnant I would estimate to be around 8 weeks and around my 6-7 week mark I had light brown discharge for a few days and never got a period or anything. I feel pretty nauseas randomly and my nipples hurt extremely bad. I'm not on any medication or birth control, I also have never had an irregular period. They always come around the 21st of every month. I've taken a few tests but they all say negative, if anyone could help me understand that would be greatly appreciated! I plan to make a doctors appointment within a week if I still don't get a positive.