I think you could try to find a different, new source of self worth to replace it with. It is probably hard to remove something from your concept of 'self-worth' if there isn't anything to replace it with. Adding things to the source also gives you something to focus on/say when you're next feeling bad about (the lack of) external reward/validation. There are many options, I'll try to list a few I've heard. Perhaps some sound better/easier/more true than others:

• People are intrinsically worthwhile and valuable. (Some religions assert this directly.)
• The things you will do in the future. (Seems like toddlers have a lot of self-worth sometimes. I like to imagine this is the source.)
• The things you want to do.
• Being able to do things that make you happy. (Can be hedonism.)
• The things you will never do. (Negative utilitarian, in some sense. You have worth for not being harmful.)
• Your relationships with others. (Pets count!)
• The validation and achievements that your communities/tribes have earned.
• The virtues you have developed. (Stoic.)
• The difficult things you have survived.
• You do things in a way that would, statistically, result in achievements and validation. You should value yourself for the expected value, rather than the specifics of today.