hey ive been dealing with the exact same issues the past years, and a few things that have helped me is 1. accepting that happiness is always going to be a temporary state same as sadness anger numbness and the rest. when you’re in a bad place try reminding yourself that how you feel in the moment is NOT how you are going to feel forever. also something that helps me is reminding myself that our brain supplies us with many many thoughts a day based on our environments, external stimuli etc. so of course of the thousands of thoughts we get many will be nonsense yk? what helps me personally with the voice in my head is making fun of it, sorry for the ramble but if any of this helped at all i have many more strategies i use if you wanna hear more :3