I just had my period but about a week and a half later, I start spotting. I've had spotting during ovulation or after rough sex but this was more than that. It was really heavy. Almost period spotting. It lasted three days. It had little blood clots and they were really hard. I thought I was pregnant but all my tests for some reason came out invalid and I was recently in the hospital and the blood test came out negative. But is there anyone that could have an idea as to what it could've been?