Yeah, I know what you mean. I'm down 32 pounds, and yet I'm still higher than I was many years ago when I started Weight Watchers because I thought I was too heavy.
Well, in between then and now I went up and down a few times.
But that's just how it was! Don't dwell on the past--it is a complete waste of time. You are where you are now, and it's a lot better than it was 21 pounds ago.
Besides, what's your alternative? What would happen if you gave up now? History pretty much tells you that answer. So really, you need to keep going and stop hitting yourself. You used to walk 2-4 miles a day? So do that now! You used to be good with restricting sugar? So do that now!
You're not crazy, but you can sure make yourself crazy if you keep on with those comparisons.

Stay in the moment! It's going to be different this time because you realize it's NOT a diet, it's a life change.
Hang in there! Don't give up!
Jay