Do you have to give an eviction notice to a tenant on a government approved form in Ontario?

I need to move into my rental house because of my separation. I am in Ontario. I gave my tenants two month notice through a letter in November to be moved out by February 1.
Now I am being told that because I did not fill out a government form that my notice is not legal. Is this true? I thought any form of written notice counted?
And is it true that you cannot ask someone to move out in February because it is the middle of the winter? The tenants say they cannot find an new place to rent and because it is winter I cannot ask them to leave in the middle of winter.
Thanks for any help.