I sent ~2800 coins from my wallet to an exchange yesterday, and got a message saying transaction was rejected for possibly being already spent (I don't remember the exact wording). Now this transaction is sitting unconfirmed, and my balance has 2800 coins deducted.

Any way I can recover them?
Will they be credited back after a while like an unconfirmed bitcoin tx?
Hi,
before you send any coins from your wallet go to help/debug window/console and use repairwallet
this command will fix your wallet balance and allow you to send coins.
Please let us know if it helped.
Running repairwallet recovered around 2100 coins. Better than nothing, I guess.

Will suck up the loss of 700 coins. A bit pissed off because I spent almost x5 the current value on them, but whatever.
At least there's some market movement now...