I'm a FTM too & the first time it happened to me I freaked out. All it is is your muscles contracting.
Happens to me every time. Also feels like it pushes the baby up but don't worry. Ur fine. May come in handy if u wanna try to induce ur labor later on too.
Thank you so much! I'm a ftm. I definitely feel better now(:
I had that happen too :p I'm 34 weeks now with a perfectly healthy baby. I wouldn't be worried.