How can I convince my parents to let me stay home at another relative's house? Please help?

My family is going on vacation to Milwaukee next Friday, but I don't want to go because I have gall stones and can't go. My dad is making me go, but I don't want to go because I have gall stones and can't go. If I tell my dad that, I feel worried that my parents would treat me like a toddler, and I am almost 18 if I tell my dad that. I also feel worried that if I tell my parents that I have gall stones and can't go, I feel worried that my parents would do what one of my mom's friends who I don't know did with one of her kids, which is to hire a home health aide even though I want to stay home with another relative like my grandparents or one of my cousins if I have gall stones and can't go on vacation. On Friends, they didn't go on vacation with their family on Friends because they don't live at their parents' house anymore on Friends because they got jobs and moved out. The only reasons why I don't want to go on vacation to Milwaukee are because I really want to watch my grandparents' TV, I really want to watch one of my shows, I have a lot of summer homework to do, I start school on August 30th, and I have gall stones and can't go. I feel worried that if I tell my parents that I don't want to go on vacation next Friday, I feel worried that my parents would treat me like a special needs child if I don't go. How can I convince my parents to let me stay home with another relative? Can you help?

Thanks.