My confidence is almost non existant?

hi good people,i have a serious problem and i was hoping you would help me...whenever am around people that i dont know i fumble,i cant say anything that makes sense and therefore no one wants to be friends with me...there is usually this tention especially whn am having a one on one conversation.its not fully the case with guys though,i can easily relate and talk to them better than women so i have more guy fiends than girlfriends.i feel so uncomfortable at parties,i cant dance infront of people or socialise with them.people say that my face is too serious and they get scared to come up to me..they say i look angry or sad[when am walkin alone] but i hardly feel sad or angry.please help me!