Ok, if you need that vital information off, you might be able to do something before you put it into DFU mode or wipe it clean.
First, did you have any kind of backup? Via iTunes, iCloud, or any e-mail accounts?
I hope so, if not, there may only be one way to save your data if it is still in existence. There is a free third-party program that you can download from the Internet somewhere called "iFunBox". I do not remember where it is, but if you Google "iFunBox iPod download" or something similar you should be able to find it. Once downloaded, install and run it and plug the device into the computer. With iFunBox you should be able to open up your device and go deep into the apps files and view and export data from it. You can then go into the apps that contain the information and search around for your information, probably within files mixed with code. If you have shallow knowledge about technical/computer things, then at least find the app(s) that you know contain your information that you want saved, and copy their contained folders out onto your desktop or somewhere on your computer's hard drive where you can find them, and I might be able to help you further.
If you have no backup, and iFunBox or similar programs cannot find any apps or contents on your device, then you may have lost it all. Keep in mind though, that iTunes usually by default backs up devices automatically when it syncs them.
You can get back to me if you have any questions or if something doesn't work out.
I hope this information helps you recover your important data.
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~Lt. Leviathan