Employment Law Questions? Ask an Employment Lawyer.
I am sorry to hear that and I hope you are feeling better. Unless you were covered under FMLA, it would be hard to pursue a claim here. The only area you could legally challenge is their failure to abide by their procedures. You had an approved absence so why were you being punished. I don't think it would get much traction in court.
Let me know if you have any specific questions.