I'm just gonna throw this out there Marvin, but what about seeking alternative payments for college. I have several grants (free money) from www.fafsa.gov
(a usa site but the Philippines may have their own program) and a student loan.
Perhaps you telling your parents that you would rather pay for your own schooling then share a room would make them realize how serious you are about having your alone time. Granted I'm no premed student (congrats by the way) but I work all day and take night classes. It sucks, but it's better then the alternatives.
If you have a school picked out talk to a financial aid officer or a student adviser. You can try talking to your high school guidance counselors or even research it online. Keep one thing in mind, most of my friends thought that getting an apartment was cheaper then a dorm room. Any garage, attic, or basement you can call home for a few years. My bedroom as a kid was an attic and you get used to it after awhile.