¯\_(ツ)_/¯
When I was around your age, I used to have the same kinda problems, but that's because I was a shut-in who lived in the middle of nowhere. When I got to the age where I could go out and about without parental supervision, I was pretty scared of people. I don't know if it's the same in your case, but it was frightening because it was totally new to me. After getting used to an ultra-small community, all of a sudden crowds of people that I didn't know made me feel lost and helpless.
Not to mention that insecurity played a lead role in my social anxiety. All those small, negative things about yourself that you keep reminding yourself about just makes you feel like complete stuff, and you start avoiding people because you're afraid of offending them or making a bad impression or making an idiot of yourself.
I avoided eye contact, I was emotionally distant and I stuttered often. Part of it had to do with the culture shock, part of it had to do with a deep fear of being humiliated. My parents tried to encourage me to be social, but they just didn't know what to say or do. It was pretty bad until I started to gradually get comfortable talking and hanging out with people.
The only way I could really describe what I felt around strangers is like it was being vulnerable emotionally. I felt that people I didn't know personally were out to hurt me. For the first few times, it really helped to ignore any negative thoughts or fears and have small conversations, occasionally joking about and playing games with people. It was still pretty tough, though.
I started to make myself to go out of my way to socialize with people, despite my fear and insecurity. After awhile, it kept getting easier to talk to people, laugh and have fun until I didn't even need to think about it. Still have small issues from time to time, but it isn't nearly as bad as it used to be.
I wish good luck to you, and I'm glad that you're getting better. It isn't easy, and I can understand what it feels like.
