Am I pregnant??

Please help, I've been freaking out! I'm only 17 and my boyfriend and I had unprotected sex and I'm not on anything. I didn't know he put it in with nothing until afterwards but it was only for like 5 seconds, he didn't come. I also traveled a few days after my last period and there was a 2 hour difference and jet lag was involved so I don't know if that will mess with it. I couldn't keep it if I was pregnant and I couldn't tell my parents because they don't believe in getting rid of it, and they'd literally kill me. Please help.