How do I tell my father that he is holding me back from my life and career?

I would really appreciate some help here! My father is very much emotionally dependent on me. He is a school teacher and apart from teaching in school, he has no other life. Honestly, his side of the family is extremely toxic and abusive (he still tries to please them though), and my mom and dad have completely different view points in life, and are more like just partners who have to live together. He is extremely dependent on me.  All this was fine when I was in school and college and had no big responsibilities, but now that I have to clear an exam for my career, it is tough for me to fulfil anybody’s emotional needs while studying whole day. To be honest, this is the time when I need his help and understanding.  My observation is that seeing me work, he is afraid that I am leaving soon. Which obviously will happen someday as I am a woman, so I will get married and leave eventually, but this career thing is too close for him maybe? While I was in school or college, he was so strict about my studies, and now he is just.... weird. Like not saying directly, but someday- randomly crying that he has no one except for me, someday-that I should know his needs because I am his daughter etc.  I really love him so much and I really don’t want him sad or hurt.  But at the same time, I want to be able to work efficiently. Most days I go out and study, but it is still not enough for this exam. I need to put extra hours! How do I handle this situation?