Cannot understand anyone spending most of their time somewhere they are unhappy, particularly if they are not even financially dependant on that job.
I had no paid employment for a couple of decades, whilst I was bringing up my children, fostering children and acting as a carer to my husband.
Applied for a part time job when I was 61 -first one after I stopped paid employment some 25 years earlier. Got that, spent a happy eight years there, gaining promotion, etc during that time. One period, thought I was going to be made redundant, applied for another job (I was then 65 years of age), got offered that one also.
So, in my opionion you are pretty young - even more so as these days official retirement age is so much higher. When I applied aged 61 years of age, I was already then one year over female retirement age.
Do not waste time being stressed and unhappy- hand in a polite letter of notice and take your time to find yourself an alternative, happy employment.