The good news is that any work that wasn’t deleted isn’t lost, those items can be brought into a new Project. To do this, create a new project and then bring in the individual scripts, tests, etc. from the old one. This is done using the “Add Existing Item” option in the Project Explorer.
How to add an existing item:
Once that selection is made, navigate to the old project and select the Keyword Test (or other item) from the old project. Repeat this process for all scripts, tests, and stores.
For the NameMapping, pick the “Merge with” option, then find the old NameMapping file in the other project.
More detail is available here at the link below.
Adding and Removing Project Items and Their Child Elements: https://support.smartbear.com/viewarticle/68345/