My brain is a curse

I overthink everything, constantly. My thoughts always go straight to the worst‑case scenario. I’m always imagining what could go wrong and planning ahead for disasters that haven’t even happened. I live in this constant state of fear, like I’m just waiting for something bad to happen. It steals all the joy out of the present moment and makes it hard to appreciate the good things when they do happen. I don’t know how to turn my brain off anymore, and honestly, I don’t know what to do.