You are right, if you are landed immigrant, you can get health insurance after your landing. However, it takes at least a few weeks to apply and receive the health card and you do not want to go without medical advice or treatment for that long. I would recommend you to buy private
health insurance in Thunder Bay to cover at least the first three months. Till then you can also try to get OHIP card by visiting local emergency room. When you apply for the insurance, you will be asked to provide the immigrants landing paper. In case your parents are staying outside the country, you can apply for international health insurance . It helps you to get coverage for emergency health issues.