As an ex cable installer, I can attest to being uncomfortable off the ground on poles and ladders at almost 22' up in the air.
To help with the uncomforable part, wear you body harness, and work at a simplified elevated distance off the ground. Lean out away from the tree, and practice drawing with your bow at full draw. When comfortable, raise your distance, and practice again and again. Then continue to practice raising your stand or platform to gain confidence in your equipment ie body harness in holding you.
I realize you have a ladder stand, but you may need a climber stand to work with to practice.
During pole climbing school, I actually freak out at just 9 feet off the ground free climbing the pole. I looked like a monkey holding on for dear life that day. But once I got comfortable with practice, I could free hand up 22' and belt off.
But I don't think I would be hunting with a longbow from a stand, and have recurves that will work just fine now.
Good luck in gaining confidence.