Disappearing Emails while using iPhone 5 IOS 7.0.4

On several ocassions already I have opened an email with iPhone Mail and while reading the email accidentally disappears and cannot be found or recovered either in the iPhone or in the main Gmail database. I could not find the email by searching, Sender, Subject, All Mail, Deleted Messages, Spam or Trash Folders. The last email I was reading was important and it disappeared to oblivion while using the iPhone, a very, very frustrating problem.

In the past I had a similar situation two-three times but later I was able to find the email in Deleted Message folder or in the back of a string of email with a particular Sender. Now iPhone just disappears the message completely. Unreliable using iPhone unless one insures that your PC or Mac Book already has the email downloaded before attempting to use iPhone to read the email content. It does not happen all the time just periodically and also makes me wonder if the email was Recalled by Sender and whether an email once received, opened and read it can the deleted by Sender!?????