Possible Retaliation?

I was recently terminated from a facility after less than a year from my hire date. I had many issues during my orientation in which I was told I was "arrogant" and "alienating other staff members", and if I did not improve my behavior I would be terminated. Since then I became more receptive and had no other behavioral problems (this was discussed my first week of work). Several months later, I engaged in an activity that is against company protocol, but is widely practiced by staff members, and I have reason to believe that management knows of this occurence yet ignores it. Three days later I was terminated for not following company protocol and disobeying professional guidelines. My peers have told me that management's actions in this case were "extreme". I feel that due to my rocky start in orientation I have been retaliated against, and would like some opinions, please.

Thank you