Is it supposed to hurt?

St

Im 37 weeks and for the past 2 days I’ve been getting period like cramps. Today they have gotten worse to where i have to stop and breathe . After a couple pains i go to the restroom and as soon as i sit a big chunk of my plug comes out. Its happened about 4 times now. Has this happened to anyone???

Ps. Im 3 1/2 cm and 70% effaced