[AlanYx]

Depending on the extent to which this is impacting your life (for example, does it extend to your interpersonal relationships?), you may want to be assessed by a psychiatrist for Avoidant Personality Disorder (AvPD). This is one of the cluster C PDs. There's a book called Distancing: Avoidant Personality Disorder by Kantor that might help you evaluate whether this is something that might apply to you.

The good news is that unlike some other clinical PDs, AvPD is fairly amenable to cognitive-behavioral and other forms of treatment.

As others have noted, you might just have garden variety anxiety (which is also treatable), or something related like ADHD. If this is really impacting your life, it's worthwhile getting assessed properly.