Jen,
I had terrible sciatic nerve pain at the end of my first two pregnancies and again after my second child was born... I have it intermittently now when I pick up my son wrong or over-exert myself. The pain and spasms are so bad that I sometimes feel like I am going to drop my 15 month old... so, I know what you are going through.
I have found the best things to do for it are:
1. Keep moving. My back always tightens up the more I sit or lie around. I have to be up and around for it to loosen up and feel better.
2. Use a percussion massager on the very low portion of your back and top of the buttocks. If you don't have one, these are a godsend for people with back problems and it will help loosen the tensed muscles and increase circulation to the part of your back that is injured.
3. Try alternating ice and heat for a day or so. 20-30 minutes of ice, 30 minutes of rest, 20-30 minutes of heat... continue... my husband has been down in the back a LOT lately and this regimen helps him markedly. He says the ice helps more than anything... I think that is because it reduces swelling which in turn takes pressure off that nerve...
I hope this helps. I think back pain is the worst of all pains and the feelings of helplessness when you can't do anything because of the pain can be such a downer. I hope you get to feeling better soon!
J.
(37 year old mother of 3 boys... 11, 5 and 15 mo.)