I discovered FIRE before I started working and so entered the work force already in the FIRE mindset. When my peers talk about where they see themselves in 10 years, they talk about being consultants or managers. Meanwhile FIRE kid over here is secretly thinking about quitting their career-job and working part-time at a cafe.
I was in corporate law. You only do that job if you see it as a life investment or you have such high expenses that you need the money. I had neither and it made the job unbearable. I did sometimes wish that I hadn't found out about FIRE until I was at least bare-bones FIRE, which I would have reached at some point anyway because I'm a natural saver.
However having FIRE under my belt has enabled me to confidently quit corporate law and do something more rewarding (community law). This is because I looked at the financial side of it all and realised that the pay difference between corporate and community law isn't actually that big. Based on a 6% average return, the numbers showed that I could do corporate law and be miserable for 8 years before reaching bare-bones FIRE, or do a job that I didn't mind for 11 years before reaching bare-bones FIRE. The choice was obvious. (I posted recently about this decision)
Now doing a job that I find rewarding and fits in with my values, I'm not absolutely dying to FIRE. I no longer wake up each morning tasting bitterness when I remember that I'm not there yet. Don't get me wrong, I still want to be FIRE (mainly because I desperately want to travel for long periods) but it isn't the only thing thats keeping me going. In fact it has made my current job way better because I see it as something that I do from 9-5.30...but it's not my sole focus or life purpose. If something is annoying me or I don't like particular politics, it just doesn't bother me nearly as much as it would if I wasn't on the FIRE path. I'm just not invested enough for my job to determine my emotions. I don't have enough skin in the game. Don't get me wrong, I work hard at my job and I contribute to the culture and I value the good things and I am invested...I've just got other things going on.
FIRE only makes your job unbearable because you never realised that not doing your job was an option. As your mind accepted that this was your forever and there wasn't any greener pastures, your emotions adapted as well.
I would seriously look at changing jobs / careers. If you are more than 5 years out of FIRE, then that's a long time to be hating going to work everyday. If you are less than 5 years out of FIRE, then it shouldn't really make that much of a difference to your FIRE date and boy is it worth it!