I was hanging out with my boyfriend tonight, watching a movie, and I went up to go to the bathroom. I noticed a somewhat solid, white clump in my underwear, about an inch and a half long and a half inch thick. This has never happened before and it was just that one clump. I just finished my period. I don't think it's a yeast infection because it wasn't a lot and it didn't have an odor. What was it? And should I be worried about it?