It sounds to me like you're not too sad to write, but that you're too afraid to write.
Here are some things that may help you to re-gain your confidence in your writing:
1. Write because you want to write, not because you're good at it or think you'll do a perfect job the very first time.
2. As is commonly stated here on AW, "Give Yourself Permission To Write Crap." When you're putting a story down in First Draft form, what matters is story, not how well you use the language. Make your language better in later drafts, but get the story down in tangible form in the first draft; that's all that matters in a first draft.
3. Writing can have a therapeutic effect on the writer. This, I believe, is why so many depressed writers do so well in the Craft. Their writing is their outlet for their frustrations, their anxieties, and of course, their depression. Think of writing not so much as a Craft to be perfected, but as a constructive way to deal with your depression.
I hope this helps you out. Blessed Be.