This is crazy. When I see someone close to me being confident about themselves, making choices with apparently low fear, taking risks to improving their lifes, I suddenly am anxious, afraid of not ever being like them, and even afraid of losing them like "oh they'll discover this brand new awesome lifestyle and I'll be stuck here with my fears and I'll be tedious and they will live their lives without me". 

Yeah, I know this is crazy. I know this is childish. I know this is riddiculous. I want to change that, but first I need to figure out why this happens. Yes, it is low self esteem. Beyond that, why? Any thoughts?