Hello dear, I can empathize with you...Your loneliness in a crowd is bothering you and me also.. As per information provided by you might be  suffering from Depression?..But first step of yours is to talk to someone close like your parents or siblings or any friend about your problems....Whether you feel like or not..trust me it will help..At the same time plan to consult a psychiatrist for detailed evaluation and Management of the case..There is a solution for everything..Trust me...