I was very similar to how you describe and after years of failures I started to self sabotage. What's the point in getting a good job if I'm just going to do something impulsive or crazy in a few months? What's the point in getting a girlfriend if I'm eventually going to convince myself I'm not good enough for her? After a while I got beaten down by constant disappointment and stopped even trying to do anything ambitious. Basically I just existed like a lizard and kept my obsessions to the superficial to avoid disappointment. I was afraid of real success because inevitably I'd fuck it all up. I stopped trying for years. I also grew up getting told I was lazy, unmotivated, wasted talent etc. It wasn't until my late 20s I was diagnosed with adhd and things became a lot clearer. Now that I know what makes me click and how to motivate myself constructively life is much more consistent.