Stressed out about life?

Lately I'm literally overwhelmed by everything happening in my life. I'm fighting with my family constantly. There are family members who are close to me that are very sick. My friends and I are always bickering and on each others nerves. I'm on the verge of losing my best friend. I'm falling behind in school in 3/4 subjects (pre-calculus, chemistry and geo planitaire) because I don't understand what's being taught to me so I feel stupid. I've got to start applying to universities because I'm graduating this year and I don't know where I want to go second year. I have to stay around here first year as my parents don't want me to leave as they don't think I'm mature enough henceforth I'll be here alone as my other friends are leaving as well as my boyfriend. I'm horrified at the thought of losing my boyfriend. I'm terrified I won't make new friends next year. I just don't know how I'm going to work everything out in my life whilst working through things being thrown at me. I know that's what you have to expect from life, but lately it's just been too much. How can I distract myself from all of this and work through it without taking a breakdown?