Writing a first draft is tough, because it's our art and we want it to be the best it can be. The problem is you're judging your story right out the gate.
A draft is like a house. The blueprint is your outline, your guidepost. The draft is the foundation and the framing. If you've ever seen new construction are you really judging it for what it can be? No you will when you see the finished product and take a walk inside and live in it. Same with a draft.
Stop fiddling with the pieces you've already written in your draft (Don't go backward to go forward), you can do that later to test the integrity of the house, aka the art, you are building and creating right now. The key is to build the foundation of the house and finish your draft!
Editing is a whole different ball game.