Pelvic pain?

Brittany • Mother of 3 beautiful girls!
I was sitting down folding laundry, and when I stood up it was almost like my DD was pushing down into my pelvic bone. I immediately hunched over onto the rocker and stood there unable to move because the pain just seemed unbearable. I eventually crawled into the bed, and am now laying down and having some Braxton hicks. I am 26 weeks and was in the hospital a few days ago for some bleeding and contractions where they told me my test was positive for preterm labor and gave me a shot to stop contractions and to help mature baby's lungs. Is this pain normal to be feeling as I'm possibly stretching or is this related to labor because I am almost certain I did not ever feel this terrible with my other babies.