Why am I different?

I was freaking out when I got to know that my supervisor is the Dean of my faculty. i had a bad history with him when he didn't give his recommendation to continue my degree. he successfully making me cry and I will never forget that day. But this is how life plays, it will make you meet people that you don't like. i wonder how many marks that I will get from him. How come other people can get a good marks and grades but not me. I think I 've put my effort in it. i don't know how to explain what I feel right now. It's all messed up.