Wait and see if this bleeding develops into a period. If you're still worried, take another test.
I did want to mention that your stomach would not be getting bigger this early. That's just bloating, which can happen before your period or anytime, really. A pregnant woman typically doesn't start to truly show for a few months. If you were pregnant right now, the baby would
maybe be the size of a grain of rice, and wouldn't be big enough to push your stomach out at all.
I wouldn't worry about telling your parents anything unless you get a positive pregnancy result. What's done is done, and there's no need to upset them if you're not pregnant.
Good luck.