Try working for the Gov't. and you will really know that you are not appreciated or that they don't give a [censored] about you. I recently retired after almost 26 years of Gov't service and learned early on the way things were.
The way I learned to deal with things at work was take it a day at a time and like others have said, don't live for the job. I had things that I liked to do outside of work that kept me occupied.
I liked my job for the most part so I wasn't miserable but there were a lot of politics involved. As long as there are more positive things about the job than negative ones, I would stay where you are at unless a great opportunity comes your way.