After typing a long email on gmail, I attached a file which I later tried to remove and in the process deleted the whole email. I looked in the trash but couldn't find it. I had not yet
put the intended address on, is that why I cannot see it in the trash?
Such mails never go in the trash, the go into outer space and are lost forever. You must start from the beginning. Had you been using some software like Outlook or Outlook Express it would have gone into the draft folder.