How can they tell you you can't get medical leave. You could go leave eithout pay. I was working when I first had to go out,(it was for a group of drs.)they said, oh yeah get better, but HR said they couldn't hold my position, that I could come back and reapply when I was better. I reported them to unemployement, and after a 3 way phone call, it was determined that they could not let me go because of having to be off for medical reason. Needless to say, they weren't happy, but they had to go along with the determination. Please look into their decision. there is no reason you should have to suffer because your company is being a butthead.
Hugs
Mary