It can feel easy or funny to be self-depricating, but you deserve the route that builds you up. There's even two ways to go about it! You can start small by replacing things like "i'm the worst" with "i'm just a person" and go from extremes to neutrals which is a huge positive step! You can also try going all the way the other way and saying "i'm the actual BEST" and just tricking your brain until it comes naturally. The world is a brighter place when your instinct is not to push yourself into the darkness.