Work on your negative self-talk.

Each time you remember something and cringe or insult yourself, you overwrite that memory with you feeling shitty about it. It's a terrible feedback mechanism.

Instead, laugh at your silly mistakes, celebrate your successes and failures, and forgive yourself.

It will take a long time to unwind the stuff you have done to yourself, but this is one technique you can just start doing - recognize when you are beating yourself up and do a little better.