The thing is I know what I'm supposed to do, but for some reason I can't apply it.

For example: I know what is needed to eat healthily, or at least have an average diet. But when I'm on my own, and it's time to cook something I spend ages in front of the fridge, the freezer, the pantry nearly having a breakdown. The reason for the breakdown: I'm hungry, but feel so worthless that I can't cook anything for myself as this would be a waste of money...

Yep, total bullsh*t I know, but that believe is so strong that I can't go against it, even if I try.