Period

Okay I hate to sound stupid. My July period was late. But August 1st I started but it only lasted 3 days. I have never had sex let alone be near a penis lol. I don’t want to sound stupid and be like I’m pregnant because there is no possibly way right? I have been traveling for the last month and I have been stressed. Could that be the reason? Please help because I am worrying myself and stressing myself out anymore.