Welcome Elle. It's an awful situation you are in, but I think the advice you have received is right on.
You have to live your own life. Take the chance you have now for freedom. You didn't make your father drink and you can't stop him either. You are only responsible for you!
Don't neglect youself! Seek out Alanon meetings! Read everything you can get your hands on...esp. the stickies at the top of the forums page. There is a lot of valuable information on here.
Learn from our experience...don't put your life on the back burner!!
Welcome to SR!