I really...really...really dislike my adoptive mother, is this a good reason? She had a bad life but..........

I'm 19 years old and live at home while going to college.Now before you say anthing,I need to save money for school and can't afford an appartment.My mother adopted me when I was 4,she is my aunt .Every day, she and my step dad fight about the stupidest things ex:who left a napkin on the table, why is there mustard on her sandwich,why didn't my dad bring her candy&she is a diabetic and wishes to kill herself and doesn't use her insulin or watch what she eats,why did I go out for a walk with the puppy or open the front door too loud.They fight for days.She wakes him up at 3am sayin he is up if she is up and he has to work that day or she blocks the door so I am late to cl or can't go.She used to pull my hair,keep walking toward me until I am against a wall and cannot move.She calls me fat,stupid, tried to sufficate me,threw me down stairs,threw garbage can at me in kindergarden,calls me a even though I am a virgin.She won't get help.My family expects me to feel sorry for her...