Is there a statue of limitation on wrongful termination of employment and slander

In 2018 my ex-wife had went up to my job where I used to work for the department of corrections and show them a whole bunch of folks pictures of me doing drugs and said that I was a big drug addict yeah I had worked in the department corrections facility for 16 years and never once have I ever failed a drug test plus I have Dcf coming to my house and drug testing me at least twice a week and I never failed a drug test but I still got fired for being a drug addict And actions unbecoming of an officer. I don’t see how I could have been fired for being a drug addict when I never fight failed a drug test and they went by everything that my ex-wife had said no matter if I told them to check the evidence because the evidence would show that she was lying they never bothered to do that they never bothered to send me to rehab or get me any kind of help they just flat out fired me and I want to know if i can Still file a suit for wrongful termination