Your doctor may not have told you this, but I bet the problem is your Canadian health insurance, which may not cover all of your likely expenses in the United States. If you are willing to pay yourself out of pocket, I'm sure the Mayo Clinic will see you next week.
When I was visiting in Canada a year-and-a-half ago and needed medical care, I had to give my credit card everywhere I went; they wouldn't take my U.S. health insurance.