in agonising pain and pregnant. help

hi ladies, I hope you can help. I've had this terrible backache for two days now and it is killing me. I can't stand/lay/sit in the same position for more than 2 min and the pain when I try to move is unbearable, I can't stop screaming and crying every time I shift or move my legs in a certain way. I know this is not pregnancy related as I suffer from backache and normally I take some strong painkillers and never get to this stage. but now I'm pregnant and my medicines are off limits as they are too dangerous for the baby. I will call my gp tomorrow, but they'll give me paracetamol and I know that it doesn't work as I'm taking it now (i have alsked my midwife). I was hoping some of you have some tips on how to get better? perhaps posture exercises (I'm so crooked right now, I can't help it), or natural remedies? something that could help without hurting my baby. I am so scared and hurt right now!