Be careful of it being a mixed episode. I just try sleep as much as possible. And try not get out of bed. If I'm down, but not tired, I try watch TV and read. The hardest part is accepting that these episodes will come and go - in hindsight it's easy enough to say, but while you're in it, your illness lies to you.
I'm sorry you're having a hard time - I'm here for, as is the rest of PC.