Hi!
The things you think about tend to expand, right? So donīt
try to shut it up. It is far more effective to speak to your subconscious in a positive way, stating what you want, not what you donīt want.
Listen to the inner chatter for a while, then apply some techniques for mindfulness/meditation:
Mindfulness helps you appreciate "the now".
I have found these very simple methods extremely helpful.
Good luck!
Kourosh