When I'm at work and I suddenly feel like everything sucks and the world can just burn as far as I'm concerned, I take a look at this picture I found on the web a while ago, printed it and mounted it on my door:
It helps me take an inward look and try to identify what exactly is it that I currently feel. When I can name the feeling(s) it generally becomes less of a blocking issue. Like a shadow under the bed that you shine a light on.
I go through each one, asking myself:
"Do I feel like this now? Why?" .
Maybe I just left a meeting where I felt the rug was swept under my feet.
"How do I feel about that now? does it fit one of these things? Oh, I think I'm just expecting fast results." Then I can plan my next steps.
This also reminds me that everyone feels these things from time to time. They are universal.
Some of them are temporary shortsighted views on a long running path (expecting fast results..).Some of them are just something to be acknowledged and dealt with (overworked).
These things are also called "Gumption Traps" (Thanks, John Crowe) and I find them quite helpful.