I had my 2017 1040 done by an outside source and now I need to amend it. Am i going to lose all of my information from the past couple of years?

I had my 2017 1040 done by an outside source and now I need to amend it. Am i going to lose all of my information from the past couple of years? I have several years worth of figures for a couple of small businesses I've had as well as vehicle figures, carryovers, etc. 

Due to circumstances back in 2018 I needed to have an outside party complete my 2017 1040. I believe I need to recreate my original in TurboTax, save it, then amend it. However, I am not certain how to 'connect' the previous years data from past returns when I open the newly created 1040 to amend it. 

It seems when I go to start a new return I am asked to import information from past years, which I did.

But then when I go to amend it, since I didn't use the past years information for the 'original' it all disappeared and will not allow me to carry through those figures. 

For example, the outside party did not any of my business vehicle or office depreciation information so it was, of course, not included on the 1040. But those are the very reasons I need to amend it, to include all of that info that was left off. Plus, I would like it to carryover to future years.  

I knew this would be a pain, which is why I have put it off. But all of my tax history and figures are in TurboTax for the last 8 years or so. It is my 'trail' of information. I have no idea how i would even start to rebuild so many tedious configurations. 

Please tell me that I am missing a setting or something similar and how I can move forward. 

Thanks so much, in advance, for any help, suggestions, or guidance anyone can provide.