It is common to show a net loss on rental property, even if you have a positive cash flow.
Many of your rental expenses are fixed monthly or annual costs (e.g. mortgage interest, insurance, depreciation, etc.); if you only had one week of rental income, a loss would likely be expected.
Even when your cash flow is positive, you can also show a rental loss on your tax return. The reason for this is depreciation expense. You get a deduction for depreciation even though it isn't a cash expense. The more valuable the property is, the larger the depreciation expense will be.