If you have a T4A with boxes 20 or 48, the CRA then says you are self-employed.

Why is TurboTax telling me I'm self-employed?

Thank you for choosing TurboTax.

Yep. I am an artist and I received a T4A from University of Guelph for having one of my art pieces put on display. Oh bother. What a mess and it has totally messed up my Income tax filing so now I have to have it all ammended.

If you haven't filed as of yet- it doesn't need to be amended. You can simply go back to enter your T4A if not already entered- continue your return from where you were at. Then when it asks for your  business address- enter your home address and your name as the business name. 

Thank you for choosing TurboTax.