How long after a "mutually separated agreement" can a case be reviewed as wrongful discharge?

On Dec 27th 2012, I was called to come into my company while I was on my mandatory one-week vacation to meet with my boss, who is the Deputy Exec Director. I agreed to come into the office, because I was under the impression the topic of the meeting was regarding a RFP project. Coincidently, I received my 2012 performance evaluation on Dec 19th, which I received a high "Exceeds Expectations" rating along with a merit increase of 3%. I was terminated for insubordination because I had a meeting with my staff and was extremely emotionally about the increased levels of mole spores in the basement area where the staff and I physically worked and I was not satisfied with the lack of information obtained from my boss about the working conditions in the area. Again, I was highly emotional, I said something to my staff that was later repeated for bate tom There needed to be a statement made about the working conditions in the basement. That statement provided to the HR manager by one of my staff members, which prompted an investigation. I was never informed that I was being investigated. I found out about the investigation during the termination process meeting. I was offered the option to remain on payroll until February 15th and the termination would be considered a” Mutually Separated Agreement”. I have worked since I was 14 years old, which is over 30 years. I have never been fired. I have been an emotional wreck. I take Xanax for anxiety and I take Lunesta for insomnia. Do I have a case for undue distress and determent because of this termination?