I wouldn't worry about calling the doctor yet. It's not like there's anything they can do for you. It's possible labor is starting soon, or you could go another 2 weeks.
It took a few days for my third baby to come after I lost my plug and had a bloody show. Don't freak, but inform your doctor so he can put it in your record.
Just note the day and time, next time you see your provider or go for delivery you have the info. Unless you have contractions and or water breaks, not much can be done.
Re: Call the doctor?
DS2 due 12/12/18