is this normal? the doctor just doesn't seem to listen

I am 37 weeks. I have been having unbearable back pain for the past 24 hours. I also have been having what is the worst period cramps of my life. No contractions or bleeding or water breaking.. just a lot of pain. It doesn't matter if I sit lay or stand it's always there. went for an NST today to check on baby. everything looked textbook according to the nurse. However the pain continues. She tells me it's normal and that several people have had it. It isn't normal for me. this is my second child. I never had any of this w my first. I don't know if I should go up to the hospital if it doesn't stop or just calm down .