Hard Drive files have gone back to original state

Hello,

I had issues with my hard drive back in July 2016 which I replaced.
My hard drive was working fine and still is, however my files which I use on a daily basis and save on my hard drive have gone back to the date of being saved in July. Therefore I have lost all the work I have done since this date.

I am guessing that there could be a virus on my computer...currently scanning everything to see if this is true. Does anyone know any secure sites that are trusted?

Is there anyway I can get my files back?! This is the one thing I really need to be a resounding 'YES!'

Thank you in advance :-)