A lawsuit for what? "Forgery" is not a civil cause of action, and your post does not indicate that you suffered any damages as a result of this.
Your second sentence here doesn't make grammatical sense.
Are you saying that your employer fired you because your employer forged your signature? That doesn't really make sense Are you saying your employer fired you for some legally wrongful reason reason (what would that be?) and forged these documents to make it appear that the employer had a valid reason to fire you? If that's the case, then your recourse is to sue for wrongful termination and, when the employer offers the forged documents as evidence, obtain a handwriting expert's opinion that the documents are forged.
That's not an illegal reason to fire you. Let's say you did follow proper procedure but your employer fired you for not following proper procedure. So what? Unless the "real reason" you were fired was something illegal, it doesn't matter, and it doesn't matter that the employer might have fabricated evidence (unless you made a claim for unemployment compensation).
Claim? Denied by whom? What does a lack of "medical evidence" have to do with you following or not following proper procedure?
Then the OP either should keep all of his/her posts in the same thread or provide relevant facts when starting a new thread.

