Difference Between a Formatted Files in USB and Deleted File in USB

So this is just happened,, last time I printed my files in the library,, but there was a trojan virus in the desktop but luckily before the whole flashdrive was virused, I already got the output in my usb which is a hard copy.

After I remove the usb in the desktop then I plugged it in my laptop to check the files if it's there,, but i see was a whole nothin. I check the TOOLS and change the settings to appear the hidden files, it appeared thought but i can't open the files in the usb. Because I don't know what happen I formatted my usb..

Then my friend recommended me to use the RECUVA to recover files such things in my flash drive. Then I tried using recuva and its excellent because I see some changes that were my files that i deleted which is that I don't need which I see on the screen right on when I'm recovering files, But after the recovery, I see so many files but,,, I CAN'T SEE THE SPECIFIC FILES THAT I'M LOOKING FOR.

Isn't really possible that in some formatted drives I can't recover some files,, but mostly i recovered files that I've deleted..

If you know guys the solution Please do share it to me,, to us

The files that I'm looking for is very important, if you know what am I talking about. :)

THANK YOU GUYS IN ADVANCE