Track bleed while recording

I'm trying to use garageband mulitracking to record songs. My usual method is to record guitar as first track, and vocals on the second track and build from there. I am using headphones to listen to the guitar track and I'm singing along to the guitar. But, when I play back the vocal track by itself, the guitar from track 1 is very audible.

This track bleed is really bad in playback.

Anyone know how to stop this?

I'm using iRig as the mic input. I use over ear headphone's for playback. I've tried noise gate, but it doesn't stop it. I'm starting to think I'll have to record one track on my iPad and the next track on my iPhone so the tracks are seperated and can't record each other.

Anyone experienced this and figured out how to stop it?