Don't do any writes to the drive. Download and run a data restoration program, most have free trials to show you what they can do.
You can first try to recover the entire drive with a partition repair tool.
HERE are some examples, and always try the free demonstration versions first to insure that they will help.
If those don't work, then go to data recovery software. I'd start with Recuva (trial available then $20), EaseUS Data Recovery Wizard, and or WinHex. Recuva has a free trial, EaseUS has a free trial that will show you what it will do, and I've had a lot of luck with WinHex recovery that included folder structure and it also has a demonstration version but costs like $45 -- but it too has a free trial.
Once you have recovered what you can, back it all up to another place too -- one backup is almost no backup.