If you are using bitcoin core, you can try to erase the transactions in your wallet.dat file with pywallet. (https://github.com/jackjack-jj/pywallet)

Then you only have the keys left in your wallet.dat. When you start Bitcoin, you'll need to start it with CLI and add the option -rescan.

Your BTC should appear in your balance as unspent. You can then send them again, with a higher fee. When that transaction will confirm, the old one will automatically be rejected because it'll be a double spend.

But in the end, it makes you able to send your BTC again. :)

REMEMBER : ALWAYS BACKUP YOUR WALLET.DAT FILE BEFORE DOING ANYTHING !