another trick to try is to not focus on the pin, but instead focus on where you want to hit. In a sense you are looking past the pin. Often times your mind with naturally center the target in your peep and when you bring the pin back into focus you will be dead on without even realizing it. So instead of trying to fight yourself and forcing the pin onto the area you want to shoot, focus on the area you want to shoot and let the pin naturally float to where it should be.
If that doesn't work and you are still really struggling, try blank bale shooting as someone above suggested. Get back to the fundamentals and not worrying about hitting a specific spot helps.
Are you shooting dots/bullseyes or shooting at a 3d/animal vitals style target? When I'm struggling shooting at a 3d/vitals style target I tend to beat myself up more and get more frustrated (I think to myself "if that was really a deer I woulda missed, or wounded it!"). To combat this i got back to shooting at dots to regain my confidence and/or form (If you miss a dot who cares? you can't wound a dot). It might sound kinda silly but i find it surprisingly helpful. Anyways good luck and whatever you do don't give up!