Im not the favourite child...?

my sister and i used to be like that except it was switched. my mum used to pay more attention to my goody-goody younger sister so i tried to prove my self worthwhile. i tried to best her in everything and it slowly ate at me. i began hating my sister because everyone loved her, the stress made me fat and in a few weeks i have t see another therapist. last year when i moved in with my dad my mom explained to over the phone the she loved me very much and she was sorry, she was just worried for my sister because she believed her to be weaker and more fragile since she was younger. she thought that i was independent enough that i could take care of myself. If you and your brother are the only kids she has then its fairly normal. you're her first child, she's going to make some mistakes with you (like ignoring you for your brother?) but its up to you to tell her about it she won't know that there's something bothering you until you spell it out for her.