Nothing but Ice every couple of hours for the first 48 hours. This is to get the inflammation down as much as possible. You really can't do much else, except use some Ibuprofen, or if that hurts your stomach, there's this over-the-counter stuff called Ecotrin that worked for me too.
After 48 hours, switch to heat for 20 minutes, followed by ice for 20 minutes, every few hours. Take the anti-inflammatory meds also. If you can move around at all, do so with care. If you can stretch a little bit, that's always good, especially your legs. Try to make them bear all of your weight these days if you can.
I don't mean to sound pathetic, but using a cane around the house when your back is really bad does help! (It takes the weight off your back) I SWEAR I'm not calling you old. It helps, that's all.
I'm sorry about your back, it's the worst! It's been my downfall for the past 15 years or so, and the pain is fucking unbearable sometimes. I hope you feel better very soon.