Yeah, at this level of network usage it is quite strange that this transaction has not yet been confirmed. The recommended fee is currently around 150 sat/byte which is not much more different than your 120 sat/byte, so my best guess is that you are simply getting unlucky. I recommend you use the following websites for fee calculations:
https://bitcoinfees.earn.com/https://btc.com/stats/unconfirmed-txDuring the next few days, your transaction will most likely get dropped from most mempools, at which point you should be able to recreate the transaction with a higher fee if needed. Otherwise, you can also use one of the many transaction accelerator services being offered by other members in these forums in the services section at
https://bitcointalk.org/index.php?board=52.0. Good luck!
