Look, I don't want to hear you indulge the bad feelings with statements like "I don't deserve it". It's disrespectful to ME for you to deny my respect for you.

I respect you because you are someone who pays attention. You have an uncanny ability to accurately read between the lines when someone is hurting, and you manage to get right to their point. You have a great sense of timing and maturity.

And lastly, nothing is doomed to continue. The same way your brain chemistry has changed to bring on this bout of depression, it can (and most likely will) change again to have you feel better again. If not, that's what doctors are for. It's all within physical reach, but being emotionally ready to take charge of it is the hard part. And that's what your friends are for.