How can I get my life back on track ?

Well like the title says how can I get my life back on track. So i'll try to sum my story up as short as possible. Well I left school in the 8th grade to take care of my mom (who has diabetes and has stomach cancer and a brain tumor) so I help around the house and help take care my brothers fast forward two years. I moved back to my hometown and my mom enrolled in a school,they had put me in the 10 grade after i took a test,long story short the tuition was to high and i had to leave. And i couldn't get my report card from the school. So i spent a half of year out of school again. fast-forward another year mom gets married bla bla bla ect.... I thought i could finally go to school again so i was think about job corp. but i was wrong had to start working my step-dad told me a grown man who is 18 should be working. Spent a whole summer looking for a job (not as easy as it looks) while i was looking for a job my step dad got arrested. So now im feeding a family of 4 of a 300 dollars check a week which really is not easy because i still have took look out for my step dad who been in jail for almost 6 months. sorry for the long story but how can i get my life back on track so i can better myself and still be able to provide for my family