My mom is pushing me away? kinda long, any advice plz? ran out of space,?

My mom & I have always had a weird relationship. But lately I feel like she is pushing me away. Last january I graduated high school & last summer i started the art institutes (biggest mistake of my life btw) and she just started acting weird & getting mad at me for what seemed like no reason. I finally left the school and decided to go to community college. Then my grandmas bf got sick so she went to live with him for a while cause he had to go back & forth to the doctor. She lives with us (moved back a month & a half or so ago) & she takes care of my younger siblings. When she left, I put school off so I could take care of by siblings. My mom & I got closer then cause we talked more. When my grandma came back, I started looking for a job & registered for summer courses. Now it is like my mom wants me to go away. Im happy just going to school & trying to find a job. I feel like she thinks I am pulling away & so she is trying to just "rip the band aid off" so to speak. I know my not having a job is frustrating for her & my stepdad but im trying as hard as I can. The way she brings up the fact that im 18 I can do whatever I want hurts my feelings. (cuz I wanted to hang out with them on Saturday. I don't have a lot of friends cuz I moved around a lot, im talking 10 school changes, 6 town changes, i made friends but they all live 2 far for me to easily hang out with them (considering I dont have a car & they don't either or they dont have gas money) on top of that its hard for me to make friends. All of the friends I have im not close to cause my mom sheltered me & I could never hang out with them outside of school. Now its like im a weirdo cuz I dont hang out with a bunch of people all of the time. I also think this has somethig 2 do with my stepdad cuz he is very social. My mom rarely hangs out with anybody outside the family if you don't count her job. My aunt is her best friend. I find nothing wrong with that, my sis is my bff. Plz help. Im in pain, need help :'(