Why am i like this

Assalamualaikum.. PMR is near , i hate this feeling when i thought that all of my brain is empty. i hate the feeling when i afraid to answer PMR but i dont study. What should i do people. Serioulsly i just dont want to feel like when i got UPSR result.  The feeling when i just ruin my future, the feeling when i regret not study , the feeling that made my mother sad, the feeling when my sister was succes but not me. Every night crying because of not get the best result cause not study. But here i am still not pay attention at my study and exam. Why am i like this. Why am i not like everyone who succed in their life. Why i cant.