Hugs Amy.

As Joeve said the cervix shortening is getting ready for labour. Has the Ob put you on any medication? (I've had 1 prem and 1 threatened pre term labour)
With mine they gave me steroids for baby and a medication called nifedipine to stop contractions. Now it might not be an option for you if your cervix is opening too fast. (mine we managed to stop because it was early labour, only minor contractions, he was then born at 38 weeks). it won't hurt to ask your Ob.

My prem was born at 33 weeks.
At 34 weeks most babies are fine. Yes they still need some nursery time, but there are generally less complications.

I know it's a scary thing, preterm labour. You are in the best place, best care possible.

I wish you all the best!