Yes, in the year of the sale you will need to file a tax form. Whether you actually owe tax depends on all the details... It sounds like this will likely add to your taxable income for income tax. For the exemption there are various requirements, including that you own it for at least 24 months. https://www.irs.gov/publications/p523/ar02.html#en_US_2014_publink10008937
From pub 523: If you did not meet all the tests in Eligibility Step 1 through Eligibility Step 5, earlier, your home is not eligible for the full maximum exclusion. However, you may still be eligible for partial exclusion if you can show the main reason you sold your home was because of a change in workplace location, for health reasons, or because of an unforeseeable event. See "Does Your Home Qualify—Details and Exceptions" [also in pub 523].