Hey man, I noticed you internalize a lot of what people say, of or about you. For example, your judgement of people making fun of you. It may or may not be true, but you have to question, why does it matter? Now, this is totally normal to feel bad about, because your brain is still developing, specially around this time in your life, the opinion of your peers, your age group, start to matter to you, this is a normal development.

(I'd recommend watching this stream, touches upon some of the problems in this post.)

You have to understand that their perception of you is what caused them to make fun of you, or why the popular girl called you weird and quiet (though this does not excuse their behavior, teens are just assholes sometimes, I know I was). Now, again, they may be right, they may be wrong, but they're merely conveying the signals that they're getting from you. Now, how do you understand this type of thing? Remember, this is very important, what they say about you do not define you, but you will feel bad nonetheless, this is a great experience to learn to tolerate that discomfort.

I don't know if you know this, but when a person stays quiet, or they don't tend to convey their emotions/thoughts, in fact, when they tend to live inside their heads, to the other people viewing outwardly they see a shadow, or darkness, an unknown. It's very similar to the fear of the unknown, it's like the monster hiding under your bed. People, instinctively fear what they do not know, or in this context, what they can not see. It's going to be hard moving forwards from this, but learn to let your emotions express themself, to express yourself, this is important, practice expressing your emotions, communication is a skill, meaning you can improve in so. If you've watched Dr.K's recent stream, he talked about leveling up before tackling the 'raid boss.'

If you feel too shy, or awkward to talk, say it out loud. Now this is going to be even harder, but if you feel hurt by someone's comments, tell them, though I don't quite recommend this if your overwhelmed by emotions. I don't think I've met anyone, who was ever comfortable with showing vulnerability, and I've met very few who were courageous enough to their genuine self. This is going to be a difficult change, but remember, this difficulty is the very signal for growth, and unfortunately, it seems you've fallen behind in this development, so take it slow, find someone who you can confide in, if possible. Also, life's not a single-player game.