Ouch
Well, let me ask, are you on G+ (Google+ = Google's better version of Facebook)?
You may have knowingly/unknowingly ticked a check mark to allow pictures to automatically backup to your g+ account (as well as kept private to you only). If you did enable this, you should be in luck. If not, it's not an easy, if possible path to recover those deleted pictures. It can be possible, but can also cost quite a bit of $ too.
Wish you luck