Sciatica

I?ve had sciatica for a couple of weeks now. I?d like to exercise, but I don?t seem to get any better or worse whether I do or don?t. The pain is worse at night and first thing in the morning. I?ve had X-rays, but they don?t show anything. Can I exercise 4 days a week to keep on my fitness schedule? My back doesn?t hurt at all ? it?s just the sciatica.