I got my "period" two days ago, but it was different than all my other periods (I'm 18 so I know what a normal period is) It was just brown, really thick, and smelled terrible. and was gone in less than a day. It was also really late, about 3 weeks actually. I took 2 pregnancy tests, both of them said not pregnant and I know I couldn't have an STD because my boyfriend and I lost our virginity to each other 3 years ago, not to mention we have never had sex without a condom. I'm really worried about whats going on with my body. any one know anything that could be wrong?