Well, your wallet should allow you to spend again once it (and a large enough amount of the network) has forgotten about your transaction.  It's not simple, but eventually it will most likely happen.

IIRC, the default setting for a Bitcoin Core node to drop transactions from their mempool is two weeks.  However, each node has their own mempool and can choose whether to abide by the default.

It's still possible that your transaction will confirm anyway though - 27 satoshi/byte is low, but it's not insanely low.