HSV 2, Valtrex and Periods

Hey! I've never had an irregular period before. Ever since I've been on valtrex I felt I bled for like 2-3 days and then my period was like non existent. Now I got my period July 21st... I still have it 11 days later. I had it regular for the 2-3 days then it was like non existent per usual and now I just went to see Lion King and came back to a crime scene I'm bleeding super heavy and I'm not sure why! Has anyone ever experienced this ?! Calling the gynecologist in the morning but I'm a little frightened.