What if something happens, and you don't have any numbers to call.

If it's an emergency, dial 911. Someone will help you with your problem. However, only call if it's a true emergency, such as you are in danger (from another person) or you cut yourself and you can't stop bleeding. Otherwise, try to find a number online or in the phone book where you could reach your parents. Where did your parents say they were going? If it's a store or restaurant, you can call the store and have them page your parents. If it's their workplace, try to find a number for where they work and ask for them if someone else picks up.