Control the narrative!
When you jump off the "sleep knowledge" diving board you'll find the pool is full of information and areas to learn and understand. I sometimes kid with Rob there's no end what you can learn about sleep. BUT if I can give you one tidbit to take with you. CONTROL THE NARRATIVE!
What do I mean by that? Well, I'm going to guess that sometimes your negative thoughts take over and lead you down a road of self doubt. Stop there! When you realize this voice is upon you, also know you have another voice. Match the negative thought by coming up with someting that is the opposite in what meaning it sends. I pray, repeating simple phrases. Sometimes, I just flash positive memories and remember happy events. What ever you find, grab it and drown out the negative. And keep doing it as the more you do, the more you control the narrative, the better you will be.