I'm an eighteen year old, college girl. I had protected sex on March 7. It was my first time, we checked for leakage....we were very safe. I expected my menstrual on the 17th....but it didn't come until the 21st, so it was four days late. It was heavy for two days and then this morning, nothing? What does this mean? The first two days were heavy including blood clots. My period usually lasts 5-7 days so why the sudden change in length? I took two pregnancy tests the day my period came, they were both negative. I'm going to take more. I don't know what to do. I can't tell anyone, I could even possibly get kicked out if anyone in my home knew. Please help me. I'm really stressed.