Pressure in my butt?

😂 I dont know how else to word this. Last night I was fine and I sat down and it felt like I sat on a dildo! The pain was random and hurt so bad I literally sat there for about 90 seconds like W.T.F.

Today I started my usual cleaning up the house and again I felt pressure in my butt like if I needed to run to the bathroom it i knew I did not have to poop I just got the odd pressure there.

I’m 36 weeks

Anyone else have this? Or what is it ?