You're sort of panicking at the shot. Rushing and not picking a spot. I know. I've been there, done that. I've been hunting with a stick for more than 50 years, and still blow a shot occasionally.
Here's my mantra now. When I have a critter in range, I tell myself, "You're either going to get the shot, or not. Don't rush it. If you get a good shot, take it, if not, let him walk." Helps calm me down ( And yes, after 50 years, I still need calming down). When I've had tim eto think about the shot this way, I've never missed.
Stick in there. It will come together for you.