What could this mean??

I woke up this morning, and after getting 9+ hours of sleep I stood up and all the sudden I felt wet down there.. I thought AF came. I am late for AF, and I've been running to the bathroom a lot recently because I have this white milky discharge, thinking it's AF. But this morning I stood up and my underwear just suddenly got soaked! I was sure it was AF, but it wasn't. It was coming from down there.. And it was watery-ish and it had little clumps of this white milky discharge. I ran to the bathroom because it started running down my leg.. after I wiped it all up, it stopped. Sorry if that's tmi, I just really don't know what to think. I haven't taken a HPT yet either. & It's not sperm because me and my partner haven't didn't have sex yesterday.