As usual, it is only by reaching out to others that I can pull myself out of my funk. I got an e-mail from my friend Leslie, who gave me a boost in the comments a couple of posts down, and then I was looking up auditions for choral groups, hoping to find a group to sing with over the summer, and I found the e-mail address of an old friend of mine, who is directing a show. I e-mailed him, he e-mailed me back, and now I feel really good.
It's a bad habit, retreating when you feel low, and one that I am inclined to do. I'm glad it worked out differently this time, before I got depressed.