Problems with Mail?

Hello all -

I'm fairly new to Macs, I just got my Macbook back in March and I haven't had any problems with it until lately.

Last week I sent a few very large emails through my mail client which is attached to my gmail account. I'm not sure what happened but while sending them, one in particular, stopped. Now, every time I open mail this email shows up under "On My Mac" under recovered up to 35 times. (Sorry, it's currently 71.) Since it's a huge email it's slowing everything down and making it impossible to use mail. On occasion when I try to delete it my entire mac freezes momentarily.

I've tried deleting it in the folder but it always comes up again when I open my mail client and multiplies. Can anyone help?

Thanks in advance.

It looks like it goes through imap. It's 132MB. This has been going on since the 9th of June at 11am. The recipient did get the email, they're just being stored. Whenever I try and move them and then quit mail mail will freeze and about 2 minutes later give it gives me the error, "error occurred could not move 71 files to trash."