Generally, the less your co-workers know about your condition, the better. As crappy as this reality is, there is still a stigma about people with mental illness---it's like "normal" folks think if they get too close to us, they might get some of it on them.

I'm very careful about whom I disclose this very personal information to; my boss is extremely understanding and all I have to do is tell him when I'm going through a bad patch. But I work with a bunch of women, and I don't care to have my mood swings be the topic of break-room discussions, or to have my authority questioned (I'm a department head) because I "might" be a little manic or a little depressed on a given day.

So, bottom line is, if you aren't ready to go back to work just yet, you probably shouldn't. OTOH, work may be the 'tonic' you need to feel like you're a part of life and not merely a spectator. It's normal to be a little nervous. But you don't owe anyone an explanation, and you certainly don't want to rely on your co-workers to supply what you need to avoid loneliness.

Just out of curiosity---you said you were supposed to read at church yesterday evening. I'm a lector at my church too (Catholic) and sometimes that really gets the anxiety component wound up, but I view it as an opportunity to practice pushing through discomfort and accomplish something good. In fact, I usually do a better proclamation when I'm quite nervous.