lost email

I had an important email sent to me the other day and saved it in the draft folder. However, it is not there now. Possibly someone has deleted it, I suspect it was purposefully done. The email was from my son’s high school co-ordinator and contained an attachment listing assignments, projects and other unfinished work that my son has not yet completed.
The deleted items folder is empty, so, what I am wondering was whether it is possible to somehow retrieve the email?