While some contact lenses provide UV protection, they don't cover your whole eye, so you still need sunglasses. Look for sunglasses that protect you from 99 to 100 percent of both UVA and UVB light. This includes those labeled as "UV 400," which blocks all light rays with wavelengths up to 400 nanometers.
Just talk to your parents. Tell them you really need a day to yourself to clear your head. Making yourself sick will only make you miserable on your day off.