The important fact is "You did a job". Some people never get to do the "job" or "work for themselves". Can you believe that for the first year of my product (infocaptor) I had zero sales. At that I kept feeling, "I did a bad job" doing the following -selecting the market -selecting the coding language -marketing and so on..

But eventually I prevailed. The product is now successful and all the learnings is only going to shorten the path to success for my new product (mockuptiger)

I like to enjoy the journey more than the destination and think financial gain is just a side effect. ofcourse you need mile posts to know that your are going somewhere and these financial gains are excellent mile posts.

So enjoy,live and learn - repeat :)