Is it legal for my job to put me on probation without any writeups?

I have been at my job for almost three years I have had some great comments made about my work in the past even won an award. Now I have been plced on probation because they say I am not showing my superiors proper respect AKA Kissing their *** when they are dead wrong, or trembling in fear when I am wrong ( I own up and accept reasonable disciplinary action). They even state that I am not allowed to look upset if something negative happens, and I cannot take a break without asking like a child (no one else has to do this). Is this legal, aren;t there steps that have to be followed before a drastic measure like this is taken? I honestly believe the probation period is just a formality (paper trail) and not a chance to be better, I truly believe at the end I will be terminated.