There's not enough information to answer your first question, "Do I need to file a 2017 income tax return?" Fortunately, the IRS provides a tool you can use that will fully answer the question. The amount of debt forgiven reported on 1099-C is included in Gross Income for the year.
If you do have to file a return, the IRS says "you must report any taxable amount of a canceled debt as ordinary income from the cancellation of debt on Form 1040.pdf, U.S. Individual Income Tax Return, or Form 1040NR.pdf, U.S. Nonresident Alien Income Tax Return, as "other income" on line 21 if the debt is a nonbusiness debt, or an applicable schedule if the debt is a business debt."
As dave_thompson_085 notes below in the comments, not all cancelled debt is taxable. IRS Publication 4681 explains under what circumstances cancelled debt is not income. It sounds like Insolvency, on page 5, may be of particular interest to you.