Confused Pre-Teen.. in Unique Situation?

My mum and dad ped when i was 7 yrs old. i'm 13 now. I was raised by my Half Brother and his wife that i had never met before my parents ped. they never treat me bad they are always super duper nice to me, but i've always sensed that something isn't the same like a bio kid. I Hate my Sister in Law because she won't act like my mom , She's really Nice never Ever mean To me. she just treats me like a big sister would treat her kid brother but i want her to be my mom. sometimes i treat her really mean, i talk really bad to her and she always does nice stuff for me. like she painted my room and got me new bunk beds and brand new comforter and did a really cool room makeover she even made pillows with my name on them I'd never met nice people before. but i yelled at her and told her she's a miserable childless hag who can't have a baby all because she wouldn't call me her son. I been Through Therapy but should i be angry for my Siblings Raising me ?