If you unironically have trouble believing in the persistance of things outside of your own immediate senses, please go talk with your therapist more.
That's kind of base level underpinnings of your existence and how you interact with the rest of the world shit.
You might have better results working with a doctor and getting perscriptions for the mind altering drugs that assist you.
Trying to trust your own brain to self assess what works and doesn't while actively messing with its chemistry it uses to do that assessment... it can work, but it's definitely choosing to do it on hard mode.