I Need Advice Please

Location: Alabama. Ok so Im going to keep the details to a minimum just in case. Basically I don't know if I have a case or who to contact or really what to do. So I've been working at this job for almost 2 years, someone who was promoted was a horrible boss and blamed people below them so they didn't take the blame. Most people let them but I tried to explain myself and immediately after this person tried to make my life hell at work tried getting me fired or get me to quit I had to fight to keep my job it was obvious retaliation I reported them multiple times this went on for months before they were finally stopped it got extremely bad then I had a medical reason I had to take leave I let my job know but I didn't have a way of contacting them during the time I was out even though it was approved but it took longer than expected so they figured I wasn't coming back so I was terminated they allowed me to come back after i explained I had no way of contacting them but only temporarily come to find out from my new boss the main boss called this a probation period which makes no sense because I did nothing wrong they also let me know that because of what happened between me and that person who made my life hell for months I was being looked at differently and needed to prove myself and turn over a new leaf which makes no sense because again I didn't do anything wrong I just reported someone obviously doing something wrong they even had to take write ups off my record because they were obviously retaliation they even told me that the person was found out to be trying to get their boss fired by making a disgusting claim that was found to be a blatant lie but some how it's my word against theirs and I'm looked at as a problem for reporting them? Im pretty good at reading people and I know they know they screwed up and are just trying to find a easy quiet way to push me out and hoping I won't do anything about it like most people would. This makes no sense I don't know what to do and if someone could tell me something it would be appreciated.