"Find it again"?
You are posting from online software which can ONLY be used for a 2019 return. Hopefully you did not use that by mistake to prepare your 2018 return. The online program is only for a 2019 return.
2018 software had to be downloaded to your own hard drive. If you did not do that already, you must download the 2018 desktop software to your full PC or Mac, then update it in order to prepare your 2018 return, which must be mailed--it cannot be e-filed.
Access your downloads here
A couple months ago? In 2020? If you bought the 2018 program did you download and install it on your computer? The 2018 tax return can only be done in the Desktop program and is only saved on your computer.
Your 2018 return ends in .tax2018. Try opening 2018 program and see if you can get your 2018 return to show up in it. Go to FILE - OPEN. Are you on Windows or Mac?