h3ha First of all, take a deep breath. Stop panicking, you did the right thing by not writing anything new to that drive.
Here is what you do right now: grab a USB flash drive, go to another computer, and download Recuva or TestDisk (or Disk Drill, though the free version has limits). Put the installer on the USB stick, plug it into your computer, and install it on a different drive than the one the photos were on. If your photos were on C:, install the recovery software on an external drive or a secondary partition.
Run a deep scan on the original drive. Since you haven't written much new data, there's a solid chance those clusters haven't been overwritten yet. Fingers crossed.