Lost of interest

I used to love medical physiology, I used to get distinction in this unit but why not anymore?? I did pretty good for my quizzes but my mid-semester exam result was like shit!! Just get a pass!! DAMN FML!! I'm so lost! I have less than 12 hours to finish the second half semester lectures but I still can't find my motivation. Why?? How?? How?? I don't want to fail. I can't fail. I'm so disappointed with myself but I can't disappoint my parents. I'm so depressed right now but I can't giving up in that way. Does crying help in de-stress? I don't want to look like Ultrawoman tomorrow morning anyway~ I heard that crying will blind my eyes. I need a shoulder to lay on. Maybe just a hug? I'm cracked...