Short temper, suicidal. To be content?

I am in a constant state of indecisiveness and confusion. Short temper, mood swings, feeling of loneliness and suicidal thoughts are regular. I am a dental surgeon currently pursuing M.D.S. Work pressure and college politics are at peak. I wish to leave studies in between as I want to earn to be independent. I want to get married but my parents are not ready for the person I'm in a relationship with. I feel lonely. I don't know what to do. I feel lonely and helpless as I'm still dependent on my father. And he is not even ready to listen to my views. I feel like ending my life. But I know I am a coward from inside. I'm afraid. I feel I'm nothing but a useless crap. No one needs me. I don't want to meet people. I feel uncomfortable among people. I hate being alone but I try to keep myself locked in my room so that I'm visible to no one.I wish my father understands me and I could get married to the one I'm in love with and live happily with him.I wish I could earn good money to be content