Why do we self sabatoge?

I'm a 19m, and I've noticed that I have a real problem with self sabatoge. I've noticed that it seems that I get afraid when things truly go good for me, and tend to intentionally cause a bit of chaos in my life. Whether in friendships, relationships, work, my passions, or anything. It seems I get scared and either pull away, or intentionally screw up when things are just fine. But then later on, I really regret it. I've been this way for nearly my entire life, and i'm not sure where I could find the root cause or overcome it. Any advice would be appreciated, thank you.