BW,
Your situation must be rough. There is a silver lining. Many of us got out WELL past your age. Making friends can always seem daunting, but trust as an adult its even harder. Try to get ACTIVE. Especially when you are young, getting int he sun, and running, or doing weights or something like that.....can really affect modd and make you feel better. Will your parents let you join a gym? It can really make a difference. PM me if you like.
In addition, just be excited about your plans come past high school. The world is your oyster! Lots of unknowns and fears.....but you got this!
I really can't believe your parents already announced to you they are kicking you out at 18. What assholes.