Archviz Project Scrubbed.... Sort Of.

Hi, guys. I’ve been working on a house in UE 4.19 for almost a month now, and decided to move ALL of the UE4 files to another HDD since my SSD was about full and couldn’t add much more. But when I opened up the project file, the models and the materials were still in their respective folders, but it was as if nothing had ever been built. Now I have to start all over again. Anything I can do to either recover the missing data or tips to avoid this in the future, if there’s nothing I can do now?