Since you used a different account this year, you'll need to login to the account that you used when filing in 2017 in order to access that 2017 return. That means you'll need to use the EXACT login (same username and password) that you used when filing your 2017 return. If you used a paid edition of TurboTax, you should still be able to access your 2017 return. If you used the Free Edition in 2017, I'll need to give you more info.
Please post back in the comments section here if you need further instruction.
*** I am NOT a tax expert. I am a seasoned TurboTax user, and volunteer to provide assistance to TT users. Nothing I post is to be considered TAX ADVICE; I bear no legal liability for responses.***