I have a sole proprietorship and I did not file business taxes with my personal taxes. Should I now amend my personal return or file business taxes separately? thanks

Can you please specify if your business if a small business or a corporate?

As a sole proprietor, your business income is required to be included in your personal return.  You will need to adjust your tax return already filed to include the business income.  The form the business income is reported on is the T2125.