So upset/annoyed by people eating?

Hey, so this is my first post.. just joined, but i am really am looking for some answers!

So i get really annoyed when people eat. I cannot stand it. I haven't been able to eat a meal with my family in a long time. When they eat, i go to a different room. If we're in the car, i put in my head phones and play the loudest music i can find. I cant even stand to eat lunch in the cafeteria anymore. During lunch period, i go to the band room and practice color guard. If im watching something on tv, and a family member comes in eating food, i ask them to just wait 10 min, for the program to be over. They never will, and i just go off on them. Also, if we go out to eat with family at their house or something, i either make up an excuse to why i cannot go or take a long walk, already claming to have eaten. I feel SO bad.. like im a horrible child for getting so upset at such a simple thing.. but i dont know whats wrong. I try to block it out, but cant. Its gotton worse as i have aged. I mean, im only 15 years old, and am worried about how bad it might get in the future. Its not only eating. If someone is in the bathroom and i can hear them pee.. i do the same thing. Or if someone is tapping their leg repeditly or twising their hair, playing with their finger nails.. simple things like this. I tense up in the musles, and cannot focus, just cant take it. Whenever im at home, i try to stay alone as much as possible. I ask nicely for my mom to stop twisting her hair, or something, and she yells and often goes "am i allowed to do anything!?" and i feel awful.. i know i sound ridiculous.. but i cannot stand it. Whats wrong with me?