I can tell by how well you write and how well you expressed yourself that you are not mentally challenged, slow, special, or stupid. Probably pretty intelligent.

That is the phrase that jumped out at me. What you describe is actually pretty common and comes from some kind of emotional block, self worth issue. Its not rational but whatever the block is prevents us from making rational decisions sometimes. Or decisions that are in our best interest. I am pretty intelligent but have had this same problem in the past. Especially around finances. Self sabotage and avoidance behavior that caused me lots of problems.

Just my take on it.