cervical mucus?

so, i believe i ovulated ed on either this past Friday or Sat. (My opk was positive on thursday and they typically say 24-36 hours till ovulation once you get a positive). Anyway, all of a sudden today i had a glob of what looked like eggwhite cervical mucus in my underwear this morning. I quickly took another OPK and it was negative. What is going on? I thought maybe it was sperm but isn't sperm usually more watery than thick and stringy? Has this happened to anyone before? i'm sooo confused!