E-mail files older than May 2015 all disapppeared-need recovery

ocsailorman Posts 1 Registration date Friday July 17, 2015 Status Member Last seen July 17, 2015 - Jul 17, 2015 at 08:03 AM
I Have been using Gmail almost from the begining. It has, over the years, become my main filing system for many types of electronic communications. Yesterday I went to look for an item which had been attached to an e-mail and discovered that EVERYTHING from hundreds of files that is older than May 27, 2015 has been deleted. I change my password on a pretty regular basis.
I use gmail on a VISTA computer (my desktop), a laptop with Windows 8.1, a netbook with Windows XP and four Android devices. I have never has a sync problem.
What happened to my e-mail files and how do I recover them?