Bad back pain

So I just got out of the hospital. I am 3cm and 50% effaced. I have on and off contractions that I can feel in my uterus but I am having immense contraction pains in my back. Like they stay and get stronger and stronger then come down like contractions in your uterus but I feel it all in my back. This is my third child. It wasn’t like this with my other two. Should I call my ob office? What can I do to help things go faster? The doctor said since I am a day away from full term that I should do my walking and squats and all that good stuff but it just makes the pain worse. They won’t induce me until I hit full term which I completely understand but for some reason my body is trying so hard to go but it can’t get past 3. It’s been 4 days now and I feel like I’m dying. I can’t pee or poop or anything because anytime I try I literally have the contractions pains in my back and it feels like my son is gonna fall out. I have been losing pieces of my plug for 2 days now and I can’t handle the pain anymore. Ladies help please!!!