Depression. Medicine for the time being?

I've lost 2 years of my college life because I wasn't interested in what I chose earlier. It was Computer science engineering. This is the third year I'm trying to go ahead with my education, this time with Business studies. I chose this field after a lot of research and taking up exams. I had developed an interest in it. But I seem to be losing interest in college altogether. I'm on the verge of losing another year and it's made me get into depression. I'm slowly losing a year, and another, and another. I don't get out of my room, talk to outsiders, or even my friends, hardly even make a conversation with my parents. I have been going through the same feeling for 3 years now and I'm fed up. I cannot go to a counselor anymore because it hasn't helped me in 3 years. I seriously do not want to feel this helpless and alone. How do I help myself? Any medicine for the time being?