I believe I just deleted an entire project by accident, but I'm trying to get it back.

First, try to find the file(s) system-wide using the search function in your OS.

If that fails: use an undelete utility to attempt to find the deleted file(s). Best to avoid using your computer, and preferably download the utility on a different computer, save on a usb drive/key, and run it directly from there on your computer. Then check if it can find your deleted file(s) and undelete them.

KickAss Undelete may be able to retrieve it:

http://kickassundelete.sourceforge.net/

Failing that, your file(s) are lost, unless you kept backups. You did keep backups, right? It seems you did not. 

Your files are lost then.

In any case, you have learned a couple of very important lessons:

1. Never ever use the single recovery file to keep working. Save a new version someplace else.
2. Never ever lose track of where your files are saved. Create a project folder for each project, and keep all project related assets and files in that folder. Do not mindlessly rely on software to do this for you.
3. Never ever keep working with one single file. Create new versions when you hit a milestone. V1, V2, V3, etc. to avoid losing all your work to a corrupted file.
4. Never ever forget to create regular backups of your important working files. Install some kind of automated backup tool that does this automatically for you while your work or at the end of a session.