That depends. If you have had unprotected intercourse since your last period, then to be safe you should probably get a pregnancy test. However, it is perfectly normal to have irregular periods, especially if you have been under a lot of stress recently. I wouldn't really worry unless you are over two weeks late.
I'd find out if you are pregnant before bringing your parents into it. No sense in freaking them out if it turns out there was nothing to worry about in the first place.
Even if your period has been on time it's not unusual for your body to randomly decide to be late. I wouldn't worry until after 2 weeks. If you drink, though, I'd avoid alcohol until you know for sure.