Are back spasms normal after having lumbar microdiscectomy surgery 2 weeks ago?

I had a discectomy on 10/30/10,,,,almost 3 weeks ago, i was fine the first 2 weeks and only had to take advil for the discomfort but then i started getting sever back spasms. It took me 5 hours and alot of meds just to be able to get out of bed one day. The dr says these spasms are normal but i have never been so scared in my life and am now afraid to move at all in fear of yet another spasm coming.........