Your transaction does have a very high priority, which is about 12,122,931,937. This qualifies it for a free transaction. I believe that you didn't select a fee and Bitcoin Core assumed that it would be confirmed due to the priority and the size.
Bitcoin Core automatically rebroadcast and I doubt it would be confirmed anytime soon, especially since the network load is extremely high. You can force Bitcoin Core to stop rebroadcasting by running Bitcoin Core with -zapwallettxes command. For example, navigate to your Bitcoin Core folder, copy the directory. Open command prompt and key in this
"C:\Program Files\Bitcoin\bitcoin-qt.exe" -zapwallettxes
. It would depend on your OS or where you installed it. Just run it with -zapwallettxes and you will be fine.
Given that it probably didn't propagate very well, you can construct another transaction with fee after a day of waiting.