This Canada Revenue Agency (CRA) page can help you determine if you are a resident for tax purposes: Determining your residency status

If you are still unsure of your residency status, you will need to contact the Canada Revenue Agency (CRA) and confirm it with them. 

If you are in Canada or the United States, you can call the CRA at 1-800-959-8281. If you are elsewhere, you can call 613-940-8495. This page has more ways to contact the CRA: Contact the Canada Revenue Agency