How do I build a better relationship with my parents , even tho I really can't stand them?

Hi , my name is frenchie. I am 17 years old and I have a terriable relationship with my mom and dad !!!!!!!! I like to say I hate their mother ******* guts and I wish they were dead !!!!!!!!!!! Even tho I don't mean it !!!!!!!!! I try so hard to do everything right !!! They treat me like **** tho . They treat me way diff . then all my siblings! To add to the drama I am adopted!! They always make me seem like I am juvenile, and a bad kid !!!! When compared to my siblings I am good !!!!! All of my siblings smoked pot everyday in highschool, they got wasted every weekend !!!!! They losttheir virginitys at the age of 15 !!!!! The only thing they were good at is school !!!!! I never do any of thosethings ! Including school, I am not very smart so my grades aren't good !!well I p everything I'm just not a straight A student. I am also fatter then all my siblings and my parents make me realize that everyday of my life !! Making comments like" wow are u pregnant, I wait that's ut fat!!! Stop eating u already look like a hippo" I can't take this anymore !!!! I don't really want a better relationship , I just know that I will grow up the rest of my life hating my family , and I don't want that because sometimes I love my family , and they are pretty amazing :) I have a fret relationship with my siblings it's just my parents !!!!! Help me please !!! I'm pretty emotional right now and I need help