Get your resume in order and start actively searching...

Avoid trying to "get them back" - will only hurt you in the long run.

In the meantime "pretend" if necessary to be completely fine with everything and hop on the "bandwagon" of things they supposedly gave you the final warning for...

As a side note: The grass isn't always greener on the other side - but it is worth looking at - seeing what other employers expect and what they pay in your area.