TMI but need help!

Okay so my period is supposed to start tomorrow but when I woke up and went to the bathroom I had a long clear jelly like string coming from my vagina, there was no smell to it. I’ve looked it up and it says either that I’m ovulating or that its an early sign of pregnancy! But if my period is supposed to start tomorrow I can’t be ovulating... has anyone else experienced this?! I take the birth control pill but I’ve been on it for 3 months and haven’t experienced this until today.... please help! I don’t want to call the doctor it’s kind of embarrassing lol