When you think about the road you are going to take tomorrow, when to resign will not be the cause of your pain. According to your description, this situation is really hard, but will your next job be better than this one if you quit? What kind of industry will you choose in your next job? You should have a plan in mind. Therefore, my advice to you is to think about other industries or jobs that you can jump into, sort out your own abilities and resources, and see if there are more suitable places to go. When you have some planning and preparation, you can resign calmly. Even if you quit your job for a while and just stay at home and relax, you have to have a rhythm in your heart and know what to do next. Good luck!