Dream About Failing Biology Exam At Night

I dreamt I was taking the biology exam with my friends at night. But then i blacked out and teacher called me alone to do the test. It was 1 am and I had slept off due to exhaustion. So I told her I'll do it at 5 am in the great hall with the other people, so she let me. But during the exam in the great hall, I didn't get time to revise. It was very dark and grim and I couldn't remember anything. So I demanded a retest but the teacher said she won't. I almost cried when I remember this was a dream and we already had out biology exam. Then the dream shifted to be more lucid but I woke up too soon. And after waking up I realised, I don't have biology at all, I'm a social science major