You sound like a very intelligent and capable person, but that doesn't mean that all of your thoughts are intelligent and worth your attention. Some parts of your brain come up with really stupid or useless thoughts. For example, you have a lot of all-or-nothing thinking here (you use the word "never" a lot), and you discount the positive things you've accomplished (you've saved a lot of money and have high passive income, but it took you a lot of time...).

I'd recommend taking a look at this short list of "The Ten Forms of Twisted Thinking": http://cnysearch.com/twist.htm It might help you see the holes in your thinking. Although it may be distasteful, a psychologist may also be able to help you find which ideas are twisting your perspective so negatively.