Developing meta-cognitive and emotional skills during PhD?
I empathize, as this is something that I (and many others here, I am sure) have also struggled with.

My first piece of advice is simple but difficult: you need to start valuing yourself. Eat well. Sleep well (or at least defend an eight hour block of time where you lie in bed and rest). Get outside and move around. Your mind lives inside your body, and you cannot build on a broken foundation.

My second piece of advice is to help yourself do this by getting help from a therapist. I particularly recommend looking into cognitive behavioral therapy, given your description of self-regulation: it is very good at helping people get out of dead ends that are more intellectual than organic.