Legally, they are still responsible for your medical insurance for another 2 weeks, in spite of what they might have told you.

I have 4 adult children - 3 who have moved out (one came back after a bad crash), and let me say that when each of them left home (WITH our support, mind you) they each had difficulty making ends meet and dealing with logistics of life on their own since there was so much they did not account for. New tires on their used car. Keeping said used car serviceable. Insurance on said car (higher for boys, but also for anyone under 26). Toothpaste, food, drink, utilities, gas, tuition & books if you continue to college, etc. No matter how much you think you have it figured out, there are things that you cannot anticipate or simply do not consider. It's the nature of youth and a lack of world experience.

Now, I am not saying that you should remain at home after you turn 18 since I do not know your situation (though many teens complain about their parents). But, be ready for reality to shake you of the notion that you've thought of everything and that life away from parents will be sunshine, rainbows and unicorns.