Mucus plug?

TMI- I'm 24 weeks and when I just went to the bathroom there was a pretty big piece of mucus on the toilet paper when I wiped. It didn't have any blood in it though. Also my husband and I had sex last night so I'm wondering if maybe it was just my wetness and his sperm mixed? Does anyone have any idea what it is? Or if I need to get checked? My doctor isn't in because it's Sunday.