Weird problem with spending LTC...

About two weeks ago, I attempted to spend 3k LTC.
 
The transaction still hasn't made it to the blockchain, but my client shows me as down 3k regardless.  I've quadruple-verified that I sent it to the correct address, it just doesn't want to go.
 
Any way to cancel (and retry) the transaction, or to try to resend it, or something other than just write off far more than a casual tip's worth of LTC that seems to have vanished into the aether?

Thanks!