Thank you. I was sending to Poloniex two hours ago and nothing is showing on any end. I don't understand why I can't see the transaction in the gui wallet in history or anywhere to be able to check whether it was sent or not at all...very confusing.
The transaction not showing at Poloniex may not mean anything now because they have been under much heavier traffic than they were prepared for. I would wait a bit more on an update from them.
On your end though, the outgoing transactions are being logged locally by the wallet software. Since it crashed right after sending, it might not have managed to do it. I'm not using the graphical wallet software, but on the command line one I would issue the command "rescan_bc" and wait. Perhaps someone familiar with the GUI wallet can provide the equivalent.
How long has it been since you tried to send?
Did you send to an integrated address? (how many characters did the address have?)