The advice that you've gotten here should help you reason out your ... "pitching cycle." This cycle is a combination of may things that you experience in phases - but, when all of those phases are put together, it looks like one complete motion, smooth and deliberate. Each phase, as they've been explain here, requires a lot of practice and a deliberate mental awareness of what and why. Each phase requires confidence that sets you up for the next phase. Put them all in line, one after another, and there you have a pitcher's motion.
Here's a hint to doing this right - if you ever feel a lack of confidence going from one part of your pitching cycle to the next, something is amiss along the way. STOP, figure where you lost it... go back to the beginning and start over until you feel confident in where you went wrong.
For you, like any other athlete, there comes a time with customizing your performance settles you into a rhythm, a way of performance. When that happens, something will "CLICK" inside, and you'll feel that .. "I got it !"
Finally, to support all this comes some serious time management and devotion to priorities. If you can take care of business before you take the field, then you only have the business on the field to concentrate on 100%. No distractions. And don't forget you nutrition disciplines. Eat heathy, stay healthy. And if there something in a bottle that you can't pronounce - leave it. Sport and energy drinks are fine in commercials, but nature has provided you with simple, off the shelf nutrition that you body needs.
If you can have someone video you during game time, please post it. Live fire is the crucible of understanding so much in this sport. So, depend on your confidence through repetitive training.