Help Retrieving a Lost Draft?

Hi everyone,

I'm working on an indie game with a big name freelancer and had spent a number of hours preparing a big instructional email for my creative vision on their latest assignment. I wanted to save this to send after the holidays, but I can't find it anywhere. It's not in the drafts or the trash folders. I thought maybe I c/ped the text out of the email and onto my computer somewhere, but no dice. I now suspect I might have accidentally replaced the body of the email with something else in our followup messages and sent it along, "deleting" the draft by sending it with a totally different message inside.

Has anything boneheaded like this happened to others before? Does anyone know any Gmail tips and tricks that might help me track down or recover the work I've lost? Thanks in advance for the assistance.