I know that the transaction was already confirmed, though in the future if you ever have this issue I would suggest:
1. Downloading
electrum right away (if you do not already have it on hand, which is handy in general and for these kinds of situations).
2. Exporting the private key from bitcoin core and importing it to electrum (from memory you can go to the developer console and use dumpprivkey).
Electrum can't do anything Bitcoin Core can't (at least in this case). Once the transaction is in mempool, it will instantly show up in Electrum and any attempt to broadcast the same inputs in a different transaction will be rejected.