I agree with a lot of what people have said here about a job being a job. However, my personal experience on this subject is — start with defining what happiness means for you!
This is a LOT harder than you think and in trying to answer the question you will hopefully (as I did) get in touch with yourself, your emotions, your identity, etc.
As you continually evaluate these things in trying to understand what happiness is for _you_, you will automatically have an answer to your question.
JS Error `No identifiers allowed directly after numeric literal` when running http://ajennings.net/pi.html on Mac OS Mojave 10.14.6, Safari 12.1.2 (14607.3.9)
I firmly second their advice on seeing a therapist.
As you age “living your best life” will take different forms. You just have to stick with trying to “live your best life”.
Good luck and I hope this discussion here gives you some actionable advice that you can implement.