I'm 21 weeks 1day pregnant and have been having contractions since 20weeks 1 day, but the past two days they've been better and aren't as many. But now I feel like pressure/pain in my vagina. It feels like someone put a bowling ball in there, and its like on the outside of my vagina too as well as the inside. What can I do to help it?

Edit: I've also been having a lot of diahreeah today.