Sorry to hear this, Kasia. Both James and now Patti would occasionally do this, and it's really really scary, I know.
I attended a couple of clinics with Brenda Aloff when I had Alex (who was never ever aggressive to me, but pretty scary with other people and other dogs), and found her to be incredibly helpful. You can find her website here:
http://brendaaloff.com/ and I can't recommend her book Agression in Dogs highly enough. Extremely readable, and SO helpful. You can buy it from her site, or at
http://www.amazon.ca/Aggression-Dogs...s=brenda+aloff. You can also get it through Chapters, I'm sure.
I would really also suggest calling one of the behaviourists at Saint Hyacinthe...a phone consult (esp. if referred by your vet) may well be free. Dr. Diane Frank is the behaviourist there.
http://www.medvet.umontreal.ca/chuv/...portement.html
Whatever you do, do NOT do nothing. This isn't going to just go away, and could escalate, and the more stressed and apprehensive you are around him, the worse he's going to get, because he's feeding off your emotions. You know what his trigger is, so you need some advice with how to work to around it. The suggestions I've given you are a good starting place. It doesn't have to cost a lot of $$$ but it will take time, patience, and above all needs you to calm about it (hard, I know, when he's chomping on you!! I know that feeling all too well from James and Patti). But it can be done. Good luck with it!!