I am 25. I am short and lean. I am very much reversed type of person.?

My problem is that I find it very hard to get socialized. When I talk to some people, my voice tone become so humble and my friends would scold me that I talk like a slave. I don't have a girl friend so far. I am really hesitant to go and start a conversation with girls. I can be very friendly with a very small group of people. I find it very hard to walk through a place where many of my neighbors or those who know me well stand. I have noticed that some people don't like to talk to me. I think I am not good looking and tall. That's why people try to avoid me. I am really depressed. Please give me a good answer. I have to get married after one or two years. If I continue to be who I am now, I think I am really going to be in trouble.