This is my 3rd (or maybe 4th) cycle using the moon cup. It has worked perfectly up until today :( I've had no issues and very few leaks, but today when AF showed, I popped it in and it fell out after a few minutes. Over and over and over until I just gave up and pulled out my box of pads. I'm doing nothing different, obviously haven't had a kid since last cycle (lol), no weight gain/loss etc. What the heck? I'm so confused and mad/frustrated. any suggestions?