Need to know your thoughts

I'm 22 years old. National level athlete. I was homeschooling since 7th class. I had no friends to share anything with. I started sports. I was too shy to talk to anyone. I didn't understand how to talk anyone. I wasn't like this all the time. My closed ones are always been my family since I started home schooling. After few months in sports, I got new friends. We were training under same coach. Everything was really beautiful. After a year or 2, a guy created misunderstanding in the group and we all broke up. Since then I was all alone. I became very isolated, my performance went dramatically down, I was all messed up. Last year I started training under new coach. He's just 3-4 years elder than me. He's kind of cool and charming guy. My performance improved. I'm still training alone but I got someone to look after my progress. But I couldn't make a good relation with my coach. I always feel like - I'm not like others. I'm very under confident. I can't speak in public. And even 1 on 1 with my coach, I don't understand what to speak. And my coach might think the same about me. I very stupid. He ignores my message most of the time. He might think I'm not a good athlete. I don't understand how to improve myself.