I understand that you are in an anxious place. You are tired of working mega hours for people who don't really value you or your work. You have money saved for retirement, but you think you should keep working. You want to work part time, but you don't know what you would do.
And you think you are too young to retire. You don't know what you would do with free time. If you think about it, you haven't had free time (except for vacations) since before you went to kindergarten. You were a student for a long time with at least 12-16 years plus of education.
And how would you spend time in retirement? That huge expanse of time scares you. And you think you should have a plan. It's how society "trains" us. Save money, and plan for your retirement. Ok, you've been saving money, but what are you going to do with that time?
Before I retired, I thought all these same things. I was a wreck trying to figure out when to retire and planning what I would do in retirement. Now that I'm 3+ years into retirement, here is what I've learned so far...
1. If the current job is killing you, get out. Life is too short to spend 8 hours a day at a place and/or job that you hate. I know first hand that chronic stress creates all kinds of issues. I couldn't sleep. I spent my whole work week thinking about the weekend. I was always racing and never fully relaxing. I didn't have enough time for exercise or eating right or friends. Not to mention health issues that can creep up on you in your 50's and 60's such as diabetes, heart problems or cancer. You have got to look out for your own mental and physical health. And if you can't do that while in your current job, get out!
2. Don't think that you have to completely plan out your future. If you think about it, you didn't completely plan out your 30 year working life when you graduated from college. So why would you need to completely plan a 20-30 year retirement? I know that everyone asks what you are going to do in retirement. So tell them you will figure it out as you go. That's called living.
3. Start thinking about hobbies and how you want to spend your time. If you haven't retired yet, start developing those hobbies now. As an example, I started doing bead work before I retired. I took up oil painting and picked up my guitar again. Others start volunteering before they leave the work scene. Don't wait until you are retired. If you are able to work fewer hours in your current job, then spend some time on these hobbies.
4. Begin looking at yourself without a "work definition". Who are you? What are your values? How would friends describe you? You will still be you after the job, but it will be without a title, performance reviews and salary reviews. You need to start examining yourself to find out what is important to you and about you in retirement.
5. Start talking to others who have retired. Everyone has a different story, but there are some similarities. Most people start out with a plan, but things change over time. I expected to be working part time, but I haven't really been serious about looking for a job. Some people panic when they retire and think they need to work full time or completely fill up their time with activities. Take some time and relax and learn to smell the roses maybe for the first time ever.
6. Get used to the question "what do you do?". And get used to the fact that people who are working may be jealous with the "retired" answer, or they may think you are a boring person with nothing to talk about. It can be a conversation stopper at a party, that's for sure. But really, did you ever talk that much about your job in social gatherings? I know that I avoided work talk because it was stressful.
7. Realize that "retiree" covers a very wide span of ages. Some churches have 55+ clubs, and just think about the differences in lifestyle if you are 55 versus 75. Over time you will will get used to that label of "retiree" even if you don't think it fits you at your current age.
8. Think about how you spend money and how you might live more frugally. You won't have the same expendable income in retirement as you do now. But at the same time, you will find you don't need all those expensive work clothes. You may decide to eat out less, but you will have more time to cook healthy meals at home.
10. Give yourself a break. Don't obsess over this decision. Relax and realize that whatever you decide will be fine. And it will probably change over time. It may be cliche, but retirement is a journey, not a destination.