Toxic behaviours

Hello, i just want to open up here. please excuse my grammar, im not that fluent in english.

i have been struggling with overthinking for the past few years and i just realized that its out of control recently. my mind is full of negative thoughts, self doubt, self blame. lately, i want to remove my toxic habits because its affecting my personal relationships with other people. i do want to change it but i dont trust enough myself, and im full of self doubts. maybe that im not capable of changing? my mind is full of doubts. i dont know where to start and i dont know how to stop thinking negative thoughts.

please help me or give me some advice because i cannot take it anymore, its affecting my mental health and its draining me badly.

Thank you