Talk to Psychiatry on Depression, Tension

I take too much tension about everything and always think in a negative way sometimes talk to myself and sometimes (not regularly) wake up during night's due to dreams think about suicide now a day's I am not studying due to some tension and also unable to sleep like before from last 7 days. I am doing CA. I was losing my weight and now due to some tension I am eating too much again. I am not taking any kind of medication and not ever went to the psychiatric. Sometime I don't eat for 2 days and sometimes eat something in every hour. My papers are in 20 days and I haven't prepared a single word due to some tension and also taking tension of papers but not studying I don't know why. I like to be alone. During any holidays I don't even come out of my room for 2 or 3 days or see what is going outside. I love to play games but from 3 weeks I have lost interest in studying in games in everything I just wanted to be alone and free.