Don't worry about it. Eventually, the mempool will forget about the transaction and you can respend the inputs. You can also try doing a manual double spend. Next time, use a larger fee. 0.0005BTC isn't enough for a 20k bytes transaction. People with smaller transactions, like 500 bytes usually use 0.0001BTC+, so for miners, it is less profitable to confirm your transaction. When you resend it, use at least 0.003BTC in fees (0.00015BTC/kb) so it will actually confirm.