Yes, you did several things wrong. You cannot add income to a tax return that has already been e-filed. But luckily for you, the 2018 income was not supposed to be added to a 2019 return anyway, so go back and delete it. That change did not go anywhere--it was not transmitted to the IRS. But you need to fix your return in the account so it will not be messed up for the future.
You cannot use 2018 income on a 2019 tax return.
Online preparation and e-filing for 2018 is permanently closed.
To file a return for a prior tax year
If you need to prepare a return for 2016, 2017, or 2018 you can purchase and download desktop software to do it, then print, sign, and mail the return(s)
Remember to prepare your state return as well—if you live in a state that has a state income tax.
When you mail a tax return, you need to attach any documents showing tax withheld, such as your W-2’s or any 1099’s. Use a mailing service that will track it, such as UPS or certified mail so you will know the IRS/state received the return.
Note: The desktop software you need to prepare the prior year return must be installed/downloaded to a full PC or Mac. It cannot be used on a mobile device.
If you are getting a refund, there is not a penalty for filing past the deadline. If you owe taxes, the interest/penalties will be calculated by the IRS based on how much you owe and when they receive your return and payment. The IRS will bill you for this; it will not be calculated by TurboTax.