Hang in there! Two things:
1) Try to differentiate your feelings about the job from your feelings about paying off the debt. You have paid off 12K in LESS THAN SEVEN MONTHS!
THAT IS AWESOME!!!!
If you keep this rate of repayment up you will be done in no time, maybe even by the one-year anniversary of this journal! That means if you can tough it out for another six months, you will be debt-free. Even if you slow down your pace a bit, you will still be done very soon.
2)We all have bad patches at work. But if these feelings about work do not go away in another month or two, start looking for another job. Even looking might make you feel better. Your sanity matters. Having a smaller debt to pay off means you could take a bit lower salary and finish paying it off more slowly, especially if it meant you would be happier.