I feel bad for this kid because I don't like him

So, I've posted something about this before. My friends were joking around and told this random weird kid I loved him and wanted him to hug me. He believed them, so now everyday he hugs me and other stuff. It makes me really uncomfortable. He touched my inner thigh and slapped my friend. And tried to force me away from them. But he hugged me in the hallway today and he just looked so happy... My friends gave him false hope, and now I feel really bad for him. I seriously don't like him though. I think he was so happy because no one really notices him, I don't think he has many friends. He's acting like he's my boyfriend. I seriously don't like it. Like, it makes me so nervous and upset, today during lunch I was shaking. Physically shaking. My teeth were chattering, and it was 70ish degrees out. It's been stressing me out all week. Help! 
Oh yeah, I'm really shy and nervous about this stuff. Also my friend decided to tell my 11 YEAR OLD BROTHER. It's just.. No. I don't want him to know about my personal life. She wouldn't shut up though. You might be thinking I need new friends, but they've been my best friends since 4th grade. They bully my at school, after that we're all BFFS again. We are a group of 4. I just can't leave them. I know I should, but I can't for some reason. Soo.. I'm having quite the situation here. I appreciate any help! ^^