You can go to Income > Rental Properties and fill in form T776 for the four months you sub-rented. If you had no reasonable expectation of profit, you should not create a rental loss with your rental expenses. You can use "Other expenses" to report the rent you pay. You report the rent you received on the income page, under the address fields.
Depending on your province and your income, you may be eligible for benefits related to the 8 months you were not sub-renting. You can check in the Provincial section of TurboTax to see if this applies for you.