Others I've asked so far said to just "wait it out" by letting the mempool forget it.
If it doesn't exist, it's out of mempool already.
Doing some research on my own i found on
https://blockchain.info/address/1Ha2fXwmpQn84kwYc4oqsjXj8irdEHiWRD that 0.01 BTC was sent to a wallet, from my wallet, that I've never seen or own. This may be contributing to why my current tx is not clearing since this transaction would leave me having a balance insufficient to fund the recent transaction I'm currently attempting.
It seems your transaction somehow got double spent, and only one of them can get confirmed.
This transaction does not appear in my BTC Core wallet either, and the last transaction my wallet displays was one that I've personally sent and confirmed.
This is weird. I suggest to backup your wallet.dat, and start Bitcoin Core with command line options -zapwallettxes and -rescan. This removes all unconfirms transactions and reloads all confirmed transactions that belong to the addresses in your wallet.
So does this mean my wallet has been compromised?
Maybe. But what thief steals only a part of your coins?
Have you ever exported your private key? Can the transaction have been made from another wallet with the same address?