How can i let my parents know i need to get away?

This weekend, all of my friends are going to the red river gorge on a camping trip. it's just for one night and two days. My mom is an alcoholic and my dad lost his job...we're in a bit of a financial crunch, and my mom coming home drunk everyday from her new job at a bar doesn't make anything easier for my dad, who's going back to college to try and get a job back. It puts SO much stress on me and my little sister when they fight EVERY DAY, and with me being in high school, getting ready to have to think about college...i really need a break from it. but they won't let me go because #1 my boyfriend will be there and #2, they say the gorge is too dangerous. I tried to explain to them that my boyfriend is a devout catholic and that we don't plan on having until we're married...and also that the campground is a parks and recreation ground...not out in the middle of the wilderness. nevertheless, they've shot down the idea and get mad anytime i bring it up. what they don't understand is that i'm going to seriously break down if i don't get the chance to just BREATHE, and spend some time outdoors with the people who make me happiest. i have NO bad intentions in any of this, there won't be drugs or alcohol or , and the people i'm with are responsible. how can i convince them when they won't listen to me? please help before i lose it!