Wrongful termination

I was terminated from my position as an Instalaltion Manager on 9/5/06. This was upon return from a scheduled vacation. Seven days prior to my vacation, I had an extreme anxiety attack at work brought on by my boss calling me in and telling me everything I had done incorrectly the week before, minutes before a very important training session and I was unable to compose myself and had to leave for the day. I was under the treatment of a doctor for anxiety and depression at that time. I was advised by my comany's HR department to take an FMLA leave for the 7 days prior to my vacation. On the last day of my FMLA leave, I was asked by the owner's wife to return my company cell phone "In case someone needed it while I was gone." I asked her if she would like my key as well, she said that would not be neccesary because "we have already changed your security code." I believe steps were taken to fire me while I was under FMLA. The reason given for my termination was "poor performance." I was employeed by this company for a year and a half. During that time, I received two reviews, both good. I also received three raises. I was disciplined 8/3/2006 for speaking to my boss in an unprofessional manner (I showed frustration in my voice when speaking to him but did not use inappropriate language) and given 60 days to complete several improvement tasks, which I was doing. I am currently receiving UI benefits. The company appealed twice and it was determined both times that I was unemployed through no fault of my own.
I did make several mistakes at work and was following my suggested improvement plan. The HR representative who was working with me left the company while I was away. It is my belief that the owner was defferential to me and this dipleased his wife (there was never anything inappropriate between us) also, that the owner has issues with people who have mental illnesses. I have heard him say derrogatory things about "crazies." I would like to know if I have a case for wrongful termination for discrimination or any other reason. I am having difficulty obtaining a new job due to my termination status.