Please help!!!!

There is this pressure, cramp like pain in my pelvic area and vagina that started as a really dull almost unnoticeable pain two days ago but now is so bad I can’t even stand back up on my own from sitting or being in bed without crying in pain. It’s not contractions. It’s not gas or constipation. I’ll be 38 Weeks tomorrow on Tuesday I have my 38 week appointment later on today but I literally am in so much pain that I am still up because it hurts so bad I can’t fall asleep. Does anyone else or has anyone else experienced this?? I know that last Monday I was 1/2 cm, is this a feeling from dilating further? Is it my pelvic bones shifting or something? Or is there something wrong with me? I know I can ask the doctor today when I go to my appointment and I know that knowing what’s going on won’t make it go away but it’s making me so anxious that maybe if I know what it is I can rest a little easier mentally if that makes sense...