Why have I been on my menstrual period 3 times since 6/16. 1st period lasted 8 days & 10 days laters again, days later. Whats wrong. I have an iud.?

IUD can cause this. Irregular bleeding can occur with the iud, though it depends on which iud you have and when it was placed. It is important that you follow up with your provider to make sure nothing else is going on.