Next time always use 100 satoshis/byte.
No. Do not use a fixed fee rate. If your wallet supports dynamic fees, always use dynamic fees. If your wallet does not support dynamic fees, I recommend that you switch to one that does.
OP, you have a few options. You can wait and hope it either confirms or the network "forgets" about it, contact a miner and ask them to help you, or attempt an RBF double spend transaction.
For the second option, you can contact the users Quickseller
as they have helped users with this before.
For the third option, we need to know what wallet you are using as it is wallet dependent and also requires some technical skills.