Ocd affecting study. Results in exam.

Hi , i am preparing for ssc , banking etc . When always think to study 8hours a day and i sit 8 hours on chair to study but during 8 hours ,my gain is hardly 1% rest 8 hours i spend racing thoughts, watching YouTube searching about types of mental illness so that i can find mine ,posting questions on practo , downloading books about mental illness , Thats why after spending 8 hours on table chair ,i stand up with zero knowledge , But i find my mind tired like i have studied 8 hour , i think because of acting on thoughts my mind get exhausted.. I always feel i am working hard , but productivity is very less ,i put my 100% but still i get only 10% of it . I have ocd too ,ocd ( generally racing thoughts to relieving anxiety) Currently i am taking olanzapine and nexito but it just making me sleepy ,i have tried many medication but none is 100% working , my mother is schizophrenic patient but i dont have any psychotic symptoms. So plz tell me what to do to get good results in exam .