Hard to answer without knowing more, maybe there is something going on in your life you have not mentioned?
my rigid regimen and undying attachment to principle my ultimate failure
For that I would say no, rather, I would find that admirable and something to be proud of, not get depressed over.
My guess there is something going on behind the scenes maybe even you yourself are not aware of yet.
We all do go through these existiential crisis now and then; why am I here? who am I?
Sounds like one of them. They are good times to stop, take stock and re-assess your values.
Why you are doing what you are doing.
Good luck on the amateur bodybuilding; that sounds very rewarding.
If you put all your self-worth into one aspect of who you are, you are already messed up in the head and just biding your time until some event causes you to get really messed up. This is especially the case if that aspect is something physical or measurable. You'll get sick or injured and not up to your too-high physical standards. Someone will lift more, or time will set in, and you won't be able to lift as much. Or you'll reach your max, and not know why to keep going with any part of life.
If you're depressed, you should see a professional mental healthcare provider.
What else do you have in your life except the body building?
Are or is there anyone in your life except your friends (wife or girl/boy friend type someone)?
How are things at home and at work?
What has changed in your life? Did someone get married and you aren't, someone buy a house, or make a big move?
Basically it sounds as though you're not satisfied with the depth of your life. You either conciously or unconciously examined your life and found it lackin in something but you're not quite sure what it is. What I would recommend is to write up your goals, and I don't mean your weight lifting goals, leave those out for now. What is it that you want out of life, and think hard on these because this may lead you to understand what you're looking for in life. Then report back (after a week or so but no sooner).
I want to thank everyone for their replies, I do appreciate the effort you've each put into your replies. Often, the way things work in my brain, laying my issues out on the table with no sugar or cherries on top gives me great insight into myself (when there is no insight to be found). Thanks again. I'm happy to say I've been much better, and have begun to integrate a much more flexible outlook into my life.