thanks to everyone with all your good suggestions, however, something came to me in the middle of the night, you know that time when you're not asleep nor are you awake?
i'm wondering if the mics i was using were picking up the vox in the headphones? i was using a brand new pair of matched stereo mics and maybe they were picking up what i was hearing? because what i'm hearing is real faint and i've only had a few tracks recorded.
i dunno,
anyway, i have to re record the tracks in question because i didn't like the way they came out.  

Headphone bleed can be an issue but if it's on a guitar track being recorded by those mics and the vocals are showing up faintly on those tracks... well that's totally the opposite of what normally happens.
 
As in the tracks coming through the headphones as you record the vocals is a problem but vocals from headphones overpowering a guitar amp is VERY unlikely. A guitar amp is simply too loud even at low volumes to pick up faint headphone bleed and one would assume unless the amp is sitting on your desk or the mics are right next to your head they'd be too far away to pick up any bleed (and the amp would still be too loud).
 
A singer recording through a mic with the backing tracks being played back through the headphones can definitely pick up the bleed though (especially on open back mics and with sensitive microphones).
 
If you had the vox playing through your monitors then that could do it. Like maybe if you had your headphones on while recording you did not realize your monitors were still cranking out signal through the air.