A week after my period, my boyfriend and I had unprotected sex where you didn't pull out. Later that evening I noticed some bleeding. It didn't stop for three weeks. It wasn't enough for a tampon but enough for a panty liner. I went to a clinic and they cleared me from HPV, STD's, and pregnancy at the time. Two weeks later when I was supposed to get my period, it never came. Instead I became nauseous, have tender breasts, mood swings, and pelvic cramping. I just took a pregnancy test and it came back negative. I don't know whats wrong with my body and I'm getting worried.