I work in India as an associate director. I have more than 11 years of experience.
My boss is very mean and selfish. She just wants her projects to be successful and for that she has been putting so much pressure on me. I told her I have been working for 12-14hours daily and my body is not helping me. She said 'dont do continuously thankless job' . Work for 8-9 hours which will have an impact. Am I overthinking or should I just quit?
Perhaps you can evaluate what you are focusing on. According to the Pareto principle, 20% of your efforts go for 80% of your good results. Try to focus on the items that really matter. Automate and streamline if you can. Hopefully this will improve your effectiveness and lower the hours needed to be effective. That may be what your boss is hinting at (not sure). Hope this helps.
Don’t quit before you find another job right now. In the meantime, maybe have a one on one to talk about her expectations about delivery timeframe for project completion and/or see if you are able to delegate some lower level tasks to a colleague while working on the things that cannot wait.