You need to use the exact account and user ID to find it if you did---unless you used desktop software in which case the file is on your own hard drive.
Many people have multiple TT accounts and forget how to access them. Log out of the account you are in now.
Account recovery
https://myturbotax.intuit.com/account-recovery/
https://ttlc.intuit.com/questions/1901535-forgot-your-turbotax-online-user-id-or-password
Or did you use the desktop version of TurboTax? If so, the files are on your own hard drive or any backup device you used like a flash drive.
https://ttlc.intuit.com/questions/1901486-how-many-turbotax-accounts-do-i-have
https://ttlc.intuit.com/questions/1901535
https://ttlc.intuit.com/questions/1901659-find-your-tax-data-file-in-mac
https://ttlc.intuit.com/questions/1900721-find-your-tax-data-file-tax-file-in-windows
Access to prior year returns
https://ttlc.intuit.com/questions/3355524-when-does-access-to-my-prior-year-turbotax-online-returns-...
https://ttlc.intuit.com/questions/3404575-how-do-i-access-my-prior-year-2017-return
You can get a free transcript from the IRS:
https://www.irs.gov/individuals/get-transcript
How do I get a copy of a return I filed using online TurboTax?
https://ttlc.intuit.com/questions/1900748
How do I get a copy of a return I prepared using desktop TurboTax?
https://ttlc.intuit.com/questions/1900639
Note: Every year, before mid-October, print a copy of your current year tax return and save it as a tax file and pdf, too. That way you will have it when you need it for school, a loan, next year’s tax return, etc. without going through a lot of aggravation (and expense) to get it.
https://ttlc.intuit.com/questions/1899645-how-do-i-save-my-2018-turbotax-online-return-as-a-tax-data...
https://ttlc.intuit.com/questions/1912544-how-do-i-save-my-2018-turbotax-online-return-as-a-pdf
**Disclaimer: Every effort has been made to offer the most correct information possible. The poster disclaims any legal responsibility for the accuracy of the information that is contained in this post.**