My tracks won't stop speeding up on sony vegas!

For some reason everytime I record an audio track on vegas the track is sped up by on beat. I knew how to quick fix it by stretching the track out to make it the correct time but that doesn't help me when I want to record more than one track for a song it just makes it extremely complicated. It is so bizzare. I even held my mic up to my headphones to record the metronome and when I played it back it was sped up one beat from the "real metronome." I know that there has to be some option I need to change and I hope someone out there can help me because I am going crazy with this.