I feel like this most of the time:

The last couple months, I've been constantly on the edge of falling into a muddy pit.  I'm one misunderstood comment away from sobbing inconsolably for two or three days.  I'm irritable and snappy.  The you're-not-and-never-will-be-good-enough dragon whispers constantly in my mind.  I feel at fault for everything tragic, wicked, or annoying in the world.  
And while this might be a usual sort of funk for first year teachers, for women planning a wedding, for women adjusting to hormonal birth control, for Eastern Washingtonians in March when the weather forecast says rain/snow 35 degrees every day for the next ten days, I want out.  Normal or not, I want to be healed.  I want joy and peace that seems impossible right now.  I want to run from the voice that yells You're Too ______________ (stupid, lazy, fat, ugly, boring, etc) and You Don't Have Any ________________ (strength, friends, talent, time, energy).  
How do I summon the gumption to get out of bed when I am so worn down I don't have any fire left in me?