Hi Sophie, from what you've said it's not you with the problem at all!! It's them!!
Come on how ridiculous is that: "you're pointless, not worthy, not good enough..."???!!!!
Of course you're.......worthy, good enough!!!! So why let them tell you or make you believe that you're any of those things???
As for the participating in life then, yes, maybe try to go back to being less of the "people pleaser" and focus a little more on you?? And what might "please" you!!
I'd say there's nothing that wrong with being a "people pleaser" and in the right circumstances- awesome!! so don't go "beating yourself up if you're slipping into it again, if it's something about your character but just make sure you've got that balance there. And that you're not "losing yourself" in it all.
It might take people a little while to get used to, might be a little stand-offish, resentful.........at first if they're used to...........but remember you matter!!
Alison