Um I know this is silly but..?

oh it's awful to wonder about being pregnant, especially if you're young. usually it's just your mind playing tricks on you and it's something ALL women who are ually active worry about. so chances are no you're not pregnant especially with just one time of having with the guy. for me, i have a terribly irregular period so i'm relieved to have my period to know i'm not pregnant :) i hope this at least calms down your nerves!