According to the Astronomy Masters on this thread, you and 150 other people have either seen (a) the same busy plane scurrying across the western horizon at sunset all over the world, leaving a contrail that takes 39 minutes or more to disappear or (b) Venus.

Nothing to worry your pretty little head over, just move along now. And don't bother looking up at the skies again until you have a Phd in astronomy, okay?