Are you not a tax professional?  How then were you able to e-file with PTO?

It should be clear to you whether you're preparing a 2019 or 2018 return.  There is no mistake about it and PTO will not mistake a 2019 return for a 2018 return or vice versa.

In case you did make a mistake and a 2019 return was e-filed with PTO (which is the big question), your only option is to amend the 2019 return and prepare/file a proper 2018 return.

[Edit: Reversed years]