hey ladies i need help i don't get what's going on.

last week i started getting quick little sharp pains that feel like they were inside my urethra, and now today they're very persistent and a lot stronger! i was walking and it made me stop because it hurt to bad to move. i feel like i have to keep clenching my vagina to try alleviate some of the pain. it keeps coming and going but the shocking feeling lasts longer than before. anyone else feel this? if so what is it. i am 31 weeks and 3 days. thanks!