Social anxiety low self esteem Overthink

I am a person who is very shy nervous, underconfident around stranger, or in group. I am not able to face the situation, my heart starts beating rapidly in that situation and trying to escape from there. I overthink every thing. Even I have to talk to stranger virtually in text also I feel nervous very much and also if I have to talk to people whom I know but didn't talk for few months then also I feel very awkward nervous to even chat also and due to this fear I am not able to do that too. Feel like I always live in past future but not in present. Full of hopelessness and loneliness I feel always. I am totally depressed due to this things. I am not able to focus in anything due to this thing in life.             I want to be like extrovert people who easily mingle with the people interact with the people without any hesitation and fear and enjoy the moment which I totally missed and watching them make me feel why I am on earth. This way I don't want to live my life.