Problem with MacMail on MacBook Air - mail with 32MB attachment appearing in "recovered messages" folder every 12 seconds

Problem with MacMail on MacBook Air

3 days ago I failed to send a mail with a large (32MB) attachment - and it is no longer in my outbox, draft mails or sent file.

BUT a copy of this same mail now appears every about 15 seconds in my "recovered messages" folder

I noticed when I received a system error saying I had a disk almost full issue - there were over 580 copies of the mail with 32MB attachment in the "recovered messages file"

I deleted them all, and deleted the Trash

BUT the message still keeps re-appearing every 15 seconds or so. So I keep deleting them.

Since then I have not been able to receive mail (altho' I am able to send) and Mail is VERY slow

I am running MAC OS X 10.6.8

I am running Mail version 4.6 (1085)