I would consult an accountant. You could be in very big trouble if audited and you haven't claimed all of your income. If you have ever put cash into your bank account, or unaccounted for cheques, Revenue Canada could come after you. Not trying to scare you, just be aware that it is illegal to accept income for services rendered and not claim the full amount. I would imagine that re-doing your taxes to add income to it that was previously not claimed could draw attention to the auditors.