Can I file a suit for discrimination for them claiming the HEP C was a liability?

I stopped breathing and collapsed at work (a franchise of a large corporation) at the time I was on chemo for HEP C the collapse was unrelated. I was able to return to work with the only restriction being not to drive company truck until I was cleared by pulmonary doctor. My employer told me they would be unable to work me I was a liability I filed for unemployment and they agreed not to fight it as long as I went out on FMLA leave to hold my job. I returned to work and a year later hurt my back on the job. They had no problem giving me light duty now that I was cured of HEP C and I was on it until after 6 months doctors stricter restrictions made it impossible to work me. I went out on workers comp and was terminated because I refused to sign up again for FMLA leave. My questions are can I file a suit for discrimination for them claiming the HEP C was a liability and they now have told me my taxes are being held due to them claiming now that the 12 weeks of unemployment was a voluntary quit.