FF, hugs. You are in a spot, but not an impossible spot by any means. Please please do NOT let shame, guilt or regret stop you from doing what is best for you and everyone you love.
Consider this. If you had a friend who was in the exact situation you are, would you want them to come clean and get help and create an awesome life?
I'm a parent of kids your age. Trust me, they would rather (even if they freak a little at first) have you do what it takes to make your life work.
Alcoholism is a medical issue. If you had any other medical issue you or your parents would probably not hesitate to drop everything else and address it before it got any worse, before it got deadly. This is the same thing, there may be layers of shame etc involved, but under it all, it's the same.
My ex husband is a professor, and it's not uncommon for his students to take a "time out" of their education to deal with situations exactly like yours, and the profs and schools work with them...many of the profs and admins have struggled themselves or have loved ones who are facing what you face. They want their students to succeed.
Talk to someone at the school, do you have an advisor? they can tell you what needs to be taken care of as far as putting your schooling on hold for a little while. Often there is someone at the school who can direct you towards svcs and may be able to sit down with you AND your parents (if that's appropirate) and help everyone understand what's going on.
And please stay close to us here at SR, no shame or guilt required here, but lots of understanding, encouragement and support.