你可以直接去任何一个medical center,把你的健康卡给他们,他们就给你安排医生了。
你可以在google.ca查一下,你可以输入你在渥太华的方位,然后输入 medical center.就可以了。例:Ottawa east medical center 就可以找到很多选择了。找一家离得近的去就行了。如果情况急的话,你可以直接去Ottawa General Hospital急诊去看的,只要带上健康卡就可以了。
中醫診所 is not an OHIP covered WALK-IN clinic. They covered by company insurance, such as acupuncture and nature path. Many of them also need make an appointment. I am not sure a 開張證明 by a 中醫診所 is useful for your 回國治.
Go to any Walk-in-clinic, you can see a doctore very soon and he/she will refer you to a specialist Doctor (it may take weeks!). You can ask the Doctor 開張證明.
If your situation is serious and feeling too bad, go to any hospital's emergency. They'll check you and refer you to a specialist Doctor very soon! They can issue you a 證明 as you want too.