Have any of you had trouble dealing with relationships while depressed?

I had an issue the other night, I basically communicated with someone inappropriately. I had been getting depressed over things all day and just wasn't thinking clearly. I sent an email that maybe should have been written, but not sent. Maybe if sent at all completely rephrased because it came off completely wrong.

When I'm depressed my ability to communicate goes down, but my need to do so goes up.

How do people deal with this?