real labor ??

I was sitting in my birthing ball and doing hip rotations and moving around and it felt like something just changed in my belly and now my lower back is in agony and when I walk my pelvis/back hurt so bad I have to take tiny tiny steps. Anyone experience this before ?
I went into preterm labor last Tuesday and they said they weren't going to try to stop my contractions so I've kind of been in early labor for a week straight