Omg. I screwed up my exam!!! What do I do!?

I f*cked up my science exam. I was supposed to get into science extension and sht, but now I dont know if I'll even p. There was so much expectation, I was supposed to live up to them; My parents, my teachers, my expectations. I can't get into extension with this, Ive possibly f*cked up my subject selection for final year studies. I saw the exam and I felt like crying. I've come home and lost the will to do anything. Some may call it over reacting, but I feel the worst ive ever felt in a long time. How do I keep my morale up for the other exams? I don't wanna F*ck them all up. Omg.. I seriously feel like dying.