You remind me of my sister. She runs and runs after happiness and never quite seems to find it, not for the long term. Like you she is an overthinker, and a very intelligent person: she’s always believed that she can somehow think or plan her way out of unhappiness. Like you, she had lots of therapy at one point, started an OU psychology course etc. She has GAD, takes medication for it and probably will on and off all her life. She has recently made some massive changes in her life - retired from work aged 50, moved to the countryside with her wealthy partner, thrown herself into gardening etc. That was a year ago, and I can already see her ‘happiness’ level starting to ebb as she returns to her baseline of questioning what it’s all about, what’s the point, why aren’t I ‘happier’?
You said upthread that you recognised the futility of turning to externalities for happiness. Yet that’s exactly what you did - you swapped one set of externalities for another, in the expectation that they would bring you happiness where the previous ones had not. Jobs, hobbies, exercise, voluntary work, homes, gardens etc - they are all externalities. The whole point of Stoicism is living well whatever circumstances you find yourself in. And they didn’t pursue happiness in the modern sense of ‘feeling good’. For the stoics living a virtuous life that is in tune with your values is reward in itself. ‘Feeling good’ or feeling pleasure isn’t the aim. I’m a bit suspicious of ‘happiness’ as a goal tbh, I don’t believe it’s the goal of humanity to be ‘happy’ so personally I don’t pursue it as a thing. It either happens or it doesn’t, I don’t really care. I do the job that’s in front of me in line with my values - caring for my children, bringing in an income and doing the best I can at work, looking after DH, supporting my friends and family - and I let the rest take care of itself really. That’s not something I learned or achieved, it’s inherent in my personality, my temperament, my genes, whatever. On paper my sister has the better / easier / materially richer life, in practice I’m way more content than she is.
None of the above is intended as criticism. You made a big step, took a big chance to improve your life. There’s nothing stoic about deliberately choosing to remain in a miserable job or situation. But expecting a different job or indeed no job at all to make you happy? That’s not going to work. Are you living by your values? Are you able to live well, whatever circumstances you find yourself in? Those are the key questions.