What's my chance of blacking out or fainting due to an anxiety or panic attack? i keep obsessing that will happen while i'm driving.

Almost zero chance!: If you will practice conscious breathing technique and attach it to the relaxation response, you can abort any "panic attack". Think about the kind of breath you would take in if you were about to swim a long distance underwater... You would feel your chest and rib cage expand beyond that of a normal breath. Take ten of these and release any tight muscles in your body- go "limp"! repeat until calm.

It sounds like: You need to have a consult with a coounselor whon can help you develop a comprehensive plan. You do not need just a bit of reassurance or a note that you should be concerned. A counselor who knows you, can best advise you, and help you put aside what is not likley and plan best for what is likely.

Slim possibility: If you haven't passed out from a panic attack up to now, it's unlikely. General fears are of passing out, dying, or going crazy. The chances of this are slim to none. But i would certainly recommend that you pursue treatment, which is usually very effective for anxiety.