...I'm not sure if it's that you need to think less, necessarily.
Maybe you just need to talk about yourself more positively.
It's not good to self-deprecate all the time, y'know?
Course I realize that this is a genuine thing that people struggle with and is easier said than done to deal with (I struggle with this a lot also ), but if you talk about yourself in a more positive light than you'll gradually start to realize it's true.
In any case, we love and support you, Strmblsd. *big sisterly hugs*