Accidently deleted an email on iPhone and now I can't retrieve it...it's not in trash.?

I got an email this morning to my Gmail account that I need to respond to, but instead of hitting the arrow for forward, I hit the trash can. I have all my emails set to archive, but when I went back to the trash on my Gmail account, there were only 2 emails in there and the email I needed was not in there! Is there any way to get this email back? I tried going back to those accounts on the computer too, and it's not anywhere....it disappeared! I just need an email that was contained in that email.... am I out of luck?? I have iPhone 4s, latest OS, and my emails are all set to "archive" in settings.