I think writers suffer from a particular kind of mood swing:
-When writing is going good its like your made of magic. Your effective, brilliant, poignant, witty, the message of the human condition is coursing through your fingertips like lightening–and everyone’s going to love it.
-When writing is going bad its like your stuffed with sand bags. Your immobile, stuck, so agonized by your awkwardness, by your inability to properly communicate, that you start to think only a crazed masochist would willingly subject themselves to this kind of mental torture as an “unpaid hobby”…so why not just give it up? Everyone’s going to hate it, anyway…
I try to take a Zen like approach to these mood swings. Just observe them; don’t cling. Let the judgments flow past like the scent of cherry blossoms on a breeze…
Keep writing. Persistence is the key.
In fact, I’d like to officially recognize myself and all the other writers like me out there for their diligent and determined effort. If there was an award for grit, resilience, stubbornness and sheer bloodymindedness in the face of performance anxiety and self-doubt, then we would win it, don’t you think?
Busy Writing 
I think the book IS the award we writers get for our grit, resilience, stubbornness, and sheer bloody-mindedness. 🙂
And I agree about the mood swings. I’m Bipolar, so I’m swinging back and forth even on a good day. I’ve often wondered if my Bipolar is caused by my being a writer or if I write because I’m Bipolar. lol
The Zen-like approach sounds like a good one. I wish I could remember to use it when anxiety and self-doubt blow everything else out of my head.