Overthinking and Social anxiety disorde.

Since 5 years I always feel less motivated, low feeling in me. I feel nervous in talking to stranger. When I think I am not so sure about anything my tone automatically get low while speaking to anyone. I find awkwardness in unknown group. I backout in handling any situation. I only talk to people with whom I can feel comfort to talk with. I studied in boy's school. So with girl I find it more nervous, shy, hesitation to talk with. I start getting very awkward type of feel when I found surrended with girl. I have also habit of overthinking. I get indulge in past thing very frequently and always think about that I can do that thing but I haven't, I feel like regret that I haven't do in past. I also think a lot about past present future thing while saying anything and that's why I end without uttering any single word, this things happen to me also during texting to anyone. This overthinking also made me depressed always. Suggest some good yoga chakra, poses, meditation or medicine.