I don't know about Canada, but here in the US, all health care professionals/workers and anybody involved in handling this type of information just recently had to review and pass the new HIPAA compliance (Health Insurance Portability and Accountability Act):
http://www.hvremsco.org/hippa.htm
It was a very big deal, and believe me, there are very serious penalties for noncompliance. All health care professionals and workers were made very clear, the penalties of breaking any part of patient-confidentiality. But, you are not in the USA, and I don't know if Canada has something similar to this or not. But, I would imagine so. You may want to consider talking to your Dr. about why he felt the justification for doing this, and if he realizes the possible penalties for breaking patient compliance? You put your trust in this person, and he broke it. He had no right to do so. I guarantee if you were in the USA, this would be a very big deal. So maybe find out the Canadian laws (I think some of the bros posted the links) and see just how far off boundaries this guy was. If it causes you great grief (like being kicked out of your house or whatever), you should take action.