OK, so I get bullied and stuff a lot, but yesterday a guy hit me so I turned around and kicked him hard in the shin. I wear boots when I'm at school, so when I kicked him hard, he fell backward on the ground. He started crying. I got in trouble, and I don't know why. Well, I mean the rules in school are if someone hits you, then tell a teacher; but I don't think before I do things. He makes fun of me because I'm not as strong as him and because I'm ADHD. I don't know if what I did was wrong.
The reason there are rules like these in your school is because most people have trouble with restraint. Someone hits them and they hit back harder. Sometimes that can lead to an all out battle until someone finally stops. The problem is that you are hurting and that doesn't put you in the best frame of mind to decide what should be done in response. "So then, my beloved brethren, let every man be swift to hear, slow to speak, slow to wrath; for the wrath of man does not produce the righteousness of God" (James 1:19-20).
"Repay no one evil for evil. Have regard for good things in the sight of all men. If it is possible, as much as depends on you, live peaceably with all men. Beloved, do not avenge yourselves, but rather give place to wrath; for it is written, "Vengeance is Mine, I will repay," says the Lord. Therefore "If your enemy is hungry, feed him; If he is thirsty, give him a drink; For in so doing you will heap coals of fire on his head." Do not be overcome by evil, but overcome evil with good" (Romans 12:17-21).
The boy was wrong to hit you. But if it was wrong to hit you, then it was also wrong for you to hit him. You don't fix a problem by repeating it.
I understand that this all is very hard. When you have a problem you want an instant solution. You can actually show you are tougher than him by not reacting or by down playing what he did. "Oh, I'm sorry, I didn't notice you. Were you wanting to get by?" Bullies are usually starved for attention and wanting to feel they are better than others. When they don't get what they want, they will first try harder and then move on to someone else.
Just so I'm clear, I don't mean you can't defend yourself. There are numerous things you can do to keep a bully from hurting you while at the same time not being the aggressor. If you have a chance to learn martial arts, it helps a great deal. You can prevent someone from hurting you or someone else, but that is where it stops. Once the danger is ended, you don't do anything more.
So if a guy swinging at you, you can knock the blow to the side. If he continues, you might do something else to encourage him to stop. Once he stops, you walk away. That is different than what happened in your situation and that is why you got into trouble.