You get to be in control of your own thoughts. You can invite and allow thoughts that serve you, that inspire you, that ignite the sparks of joy, that motivate you to move forward or to build your dreams. And you can reject or block the negative thoughts or "voices" (you know what I mean, like when you hear the voice of some bully who put you down going into re-play mode in your mind).
One technique you can uses is to relate to these thoughts the same way you might if it was a sales call coming in on your cell phone. You can see the caller ID and you don't have to waste your time on it. Just don't answer.
Another technique is to visualize something like what The Good Witch of the North said to the Wicked Witch of the West in The Wizard of Oz. "You have no power here. Be gone!"
Just say it over and over.
You can do this!