I cannot access my 2017 return to add some more information. it says that my return was filed by mail. I haven't mailed my return. how can I open my 2017 retun?

the only option to do anything on my home screen is Download/print. it shows my tax due and that the file was printed. there is nowhere to open my 2017 return. it is as though 2017 has been closed and archived like my other prior year returns. I need to get into my 2017 file and add some interest that was received late and then e-file my return.How can I open my 2017 return?