What's wrong with me where i'm going wrong in my studies?

Sirs I have been attempting my exams from quite a long time in my pcc level but I'm unable to meet success from last 7attempts, my scores are as follows Nov2009 Accounts 28 42 41 36 48 47 Auditing 55 49 52. 45. 47 54 Law and38 43. 42. 45. 58 59 Costing. 32 34 45 58. 45 42 47 Tax. 47 56. 47. 37. 45 38 57 It sm. 48 45. 43. 47. 44 46 43 Im not knowing what's wrong with me from past 4years I haven't even smiled even once, before joining ca I always used to be so happy but not now... Stress is killing and bogging me down.. I can't go to my friends nor talk to my relatives they ask me what I'm doing I had to say I'm doing ca pcc same answer from past 4years I'm feeling shame of my selves.. I used to enjoy my studies in my 12th I used to feel happy while solving problems in exams but I'm shivering in exam hall while I'm doing the exams... The bad feelings are killing me.. I was a 79% guy in my 12 thbut to fail like this in ca exams is hurting me like hell.. I don't know what's happening to me.. I don't know how to study while these feelings cropup when I'm studying..