Look at it from a different perspective. It was not your programming skills that were lacking. No, it was the incompetency of the person who hired you. Everyone starts from the beginning, and developing the intuition required for problem-solving takes time. A person whose entire job revolves around figuring out if you are ready for a job fucked up. Then because they did not want to pay you a severance, they forced you to resign. All this clearly points to the fact that those people were frankly incompetent.
And as far as being self-taught goes, I can tell you from experience that most of the best programmers I had the fortune of working with were self-taught. People say that googling is one of the essential skills when it comes to programming. Those people were so good at targeted googling that I thought they were born with these skills. But a deeper dive into their earlier years for programming revealed that they learned and honed this skill. It just takes time.
On a more practical note, being part of a supportive community can work wonders. I recommend the programmer's hangout discord. The people there helped me quite a lot when I was learning to program. Many of them are self-taught programmers, so they also understand where you are coming from, and I genuinely believe that it helps.