We cannot know why it is is saying that. We cannot see your screen, your tax return or your account. Did you transfer a 2018 return to the 2019 return? Did you have more than one account for 2018? Did you use the right one?
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
I had the same issue with mine. I even went as far as downloading the amendment software and cannot find the issue. I felt that my 2018 return was much lower than normal (50%), though my situation did not change much. Hoping the glitch didn't keep me from receiving my proper return. Best of luck finding why this occurred for us!