Im 18, Im the Oldest Child and I NEED to move out. Help Me?

so im in a really really negative situation. Im a guy im 18 and i have a younger brother 13 and a sister 11. this shit has been going on my entire life. My mom had me when she was 19. they had a good construction business for a while until i was about 8 when they started battling meth addiction. by the time i was 9 the business collapsed the house caught fire. their addictions got worse and my grandparents took over for a year 6 months at each 2 grandparents houses. then i came back to live in the house that burnt down and my dad semi put back together but it would remind you of a crack house and that was probbly the worst for me at the time. i was 11. at 8 i made a best friend. a friend that i would do anything for and he would do the same for me.
now when i was 12 i had to be moved into a shelter then a foster home for a month before moving to my grandmas in a whole different area. I lived with her for 2 years and then moved back in with our parents at 15 because they had gotten their shit together, cleaned up off the drugs and for 2 years were clean.
around 17 my dad started drinking and within 6 months had started meth again. He went to rehab march this year for a month and got clean talked a good game. all the while my mom had been taking 20 norcos [hydrocodone/ strong vicodin] a day. she still is . they have extremely toxic relationship problems. hes abused her in the past.weve even fought fist fights my dad and i. and my mom has gotten physical with me a number of times. My dad is currently wacked the f out of his mind right now on a meth binge.hes 5’10” and is 120 pounds.
supposeably they are separating but he keeps coming back he cheats on her all the time with hookers. and she is a psychotic freak co-dependent on me. who picks her face until she has open sores and scabs all over.

my dad got laid off in december and finds side jobs here and there but they dont manage or save any money. they have gone bankrupt once.
and my mom got laid off the week before last.
our rent is 2600 a month
Im the backbone of the family i always have been even if i never really got credited for it. i take care of so much and help out a bunch.
she relys on me so fucking heavily and i am just so so so sick of the environment that is surrounding me. im just not able to be happy with such bullshit going on in my life. i could probably go on for days about how messed up it is. but whatever

my problem is what should i do.

my plan is to move out to kingsburg [45 from fresno] with his mom and grandma and find a job then move with him to fresno ca into our own place. we talk everyday and have been wanting to have our own place for more than a year now. we would make a good team. I want to move out there because its half as much in rent expense compared to 1400$ a month for a 2 bed where i live in santa cruz ca. we would both work and go to school for the spring semester. meaning im going to get a refund and drop my classes at my current college. and work until we have enough money to move out of
so im wanting to move 3 hours away from my family. and im just really worried about my brother and sister. i dont want them to get taken by cps because theyve become really attached to this area because theyve grown up here way more than i have.

oh and ive been in santa cruz since 8th grade and now im a sophomore at the junior college. and i have a sales job with cutco/ vector knives. i was making good money but lost motivation. now i kinda just want a min wage job.

so how should i bring it up and tell my mom that im going to do this.
should i feel responsible for my family. because i just feel i need to focus on myself and make the best out of MY life, cuz that really is the most important thing in the end right?

my mom is extremely controlling and is going to flip out because her nerves are straight fried after years of cuckoo brain damage doing hard drugs

sorry if i was ranting scatter brainly =]
i just wanted to vent and get some other peoples perspective
or feedback.