Self-sabotage when you experience a major life change (like taking a new job, for instance) is apparently a symptom of ADHD. I only discovered this last year when I went to see a therapist for feeling like I was in my own head, ruminating about the uncertain future, imposter syndrome, feeling like I wanted to quit, etc.

Therapy helped tremendously. Consider reaching out to a professional who specializes in ADHD/Anxiety disorders. They can help you come up with ways to cope with the feelings and make it through the adjustment period without blowing up your own plans and goals.