What Causes Severe Pain In Sciatica?

I was diagnosed with sciatica resulted from 2 slipped discs that was at the begging affecting my right leg and then now it s affecting both legs and I m using strong pain killers but the pain is still there also I have numbness in both legs and pain. I m having a strange thing which is that I sometimes have difficulty peeing though I drink a lot of water and I don t do stole when I do I have a severe pain in my stomach before going to the toilet. I wanted to know what would be my next step.