hi
I'm 21 years old, 5.6 tall and weight about 145 lbs. I lost some weight during last year. I had my period june 24th, 5 days late. They lasted about 6 days, which they normally do. All though they were abnormally light. But then about 6 days after they had stopped, I had my period again.They've now lasted 6 days and it does not seem that they're stopping. What might have caused this? I have been a bit stressed lately, cause I had big exams. Could stress cause something like this?

I'm not on birth control btw.