Been there. Remember the immediate priority of work is to satisfy your personal security so that means cash. Always. Then remember it's someone else's cash. If you are an employee and it goes to shit it's not your problem. Just think of the cash building up, not the carnage, chaos and mayhem. Picture yourself as an outsider looking in and distance yourself from it as much as possible. It's not worth killing yourself with effort or concentration over someone else's shit show.

With that in mind, write down what you want out of your life and job and set some simple easy to achieve short term objectives. They might be health or learning related. Then go out and do them. This will build motivation to actually deal with the issue which is the job sucks and you need to change it. Write down criteria for your new job and spend your time finding it. Don't just jump on the first thing.

It's really important to get yourself together mentally before you jump ship though because it's very easy to end up in exactly the same situation or worse if you make a rash uncalculated decision.