My period is due any time now, but I'm not having any PMS symptoms. I'm thinking it could move onto a later day in the month, since they're sort of irregular. But I put a tampon in just in case my period started during exams. And when I took it out, there was some yellow discharge on it. This sounds gross, but it kind of reminded me of snot when you're sick? There's no odor or itch. And I know it isn't an infection. There's also some slight cramps. What could this be?