90 day probation period and workers comp.

I was working for a company for about 3 months. (Since May 15th 2006) On August 15th, 2006 I hurt my back at work. I notified my employer right away, but they still wanted me to work. When I told them I need to see a Doctor they replied "Okay, if you want to play that game." I have been having alot of problems with my supervisor from day one of working there. I got into an argument with my supervisor and told him that I am not dealing with this anymore. I was finally sent to thier doctor to be checked out. The doctor said I just have a minor sprain and I can probably return to work in a few days. When I went back to my employer to let them know the news, My supervisor told me that they have excepted my resignation and I am no longer employed for them. When I told him I am not quitting, he said that does not matter because I am still within my 90 day probation. That is not true. If you count 90 days from the day I started, My probation period ended August 12. My supervisor said I took a personal day for a court date last month, and my 90 day probation starts over.
My question is:
I feel I was let go because I filed a workers comp claim. Can I do anything about that?

Also, Is it true that your 90 day probation period starts over if I took a day off for court?