stress level threw the roof and still riseing

okay so I have this problem a lot. I didn't know where to post this..
but anyway I have been so stressed out. I am graduating high school in 4 months and I am so stressed about it. I don't know what I want to be or what I want to do. everyone is pushing college on me. saying if you don't go to college you wont get a good job and you wont be able to support a family. but I don't want to go to college. ive thought about the military but deiced against it. ive thought about working with my dad. or going to the fire academy but I just don't know and that jacked my stress up way high and now all these girls are trying to drag me into their drama and all this nonsense. BUT now my brothers girlfriend is transferring to my school and my parents told her without asking me first that I will look after her and make sure she fits in. they don't understand how much I have on my plate right now. im having enough trouble making past this year worrying about myself! now I have to look after another person! this is just wat to much for me to handle right now and I cant tell them I cant look at my brother gf because im to stressed they will most likely tell me to get over it. like UGH! I need to bring my stress level down fast before I snap. im literally losing my mind. im hearing pterodactyls out side my window and im spazing out because a light turned on and off on its own. I told them that stuff and they laughed at me. someone please help!

Have you talked to your counselor at school about this yet?

That might be the best start. I would do that. Also, you don't have to be responsible for anyone but yourself. Believe in that, trust in that.