Hospitalization leave 1st trimester

I’m under huge amount of work stress and one of the reasons is that I am unable to focus at work due to fatigue. I was called out for dozing off today at work and was told to get my act together. As I am a teacher, I don’t have annual leave, I have 3 more days of sick leave and have daily long hours. My boss is unable to reduce my workload for me and has told me to get used to my symptoms. I am not supposed to get my team to carry my weight as long as I am in office. My gynae is unwilling to give me hospitalization leave for rest as I am not having a medical problem. Her solution is to negotiate with my boss. I have thought of resigning but I still need to complete the school year. It feels like I can only get HL if I cause myself to bleed or something. I dunno what else I can do.