Why does everyone bullying me for no reason?

Literally everywhere I go, people bully me. All I do is walk around and do what I have to do without bothering a single thing or person. I always keep to myself. People always call me a retard and say that I have down syndrome. Of course they think I'm ugly too. They spread rumors all of the time. They treat me like I have no feelings, that I can't understand English, that I can't hear them even though they are loud, etc. Some people know I do hear. When they try to talk to me, they wonder why I am mean to them for what they think is "no reason". They start to be mean to me more. I have Asperger's syndrome, but now I think I actually have mental retardation (intellectual disability) and down syndrome because of what they say every single day. (I MEAN NO OFFENSE TO PEOPLE WHO ACTUALLY HAVE MENTAL RETARDATION AND DOWN SYNDROME. I WILL AND DO RESPECT THEM MORE THAN "NORMAL PEOPLE" ACTUALLY DEPENDING ON HOW NICE THEY ARE.) I have started experiencing this when I was in the ninth grade. I get tormented everyday because of how I look, so I started walking with my head down everywhere and feeling ashamed for being alive in the first place. People still hate me completely to this day. Some people in my classes at school take pictures and mimic me to get laughs or get a reaction or something. I do believe that somehow everyone in Georgia (and most likely other states) knows me and will do everything to make fun of me and hurt me in anyway. No one touches me though for some reason. Someone did say that they want to hit me and beat me up, but they never did because they may be scared or something. I don't know. Now I completely hate myself.