Ugh, I hate mean girls :( Help?

How can I get REVENGE on my 'friends'? Here's what happened: Friend A had been plotting doing the great friend switch over for the entire year. I always knew she was trying to become one of the Whores. But all of a sudden she decided to not talk to anyone in our group. I was the only one who noticed her silence and even went out of the way by texting her, "Hey is everything alright? You were really quiet at lunch." She said, "Yeah.". And then I wrote that she could talk to me and everything if something was going on. She never texted me back. So at school she had sometime formed this secret little bond with Friend B, who's literally 2 feet tall, like a midget and both of them ignored me all lunch while they talked amongst themselves. Whatever, I talked to my other friends at the table. (Personally, I always hated Friend B rather than A more) So then my friend leans over and whispers something to me because she doesn't want the whole table to hear it. It honestly had nothing to do with the other girls, and a full-one war was never what I wanted; I had even accused Friend A of 'hating me' and teasing her about it, while she ignored me practically, looked past me as if I weren't even speaking. And I never did anything to make her like this, that's what I don't understand! It's her problems that are making herself pick on me, the low self-esteem I always knew she had, the works, the stereotype. And well I guess she HAD noticed me, pfft, because then I see HER smirk deliberately at ME and lean over and pretend to whisper in the other girl's ear. So, I was EXHAUSTED from nights of little sleep, and it all piled up on me then, so I exploded. Stuff like this drives me crazy. And now they have this little posse and I sit with a different group and my other friend. But the goddamn Friend B, the midget, is getting on my nerves. I hate her. I hate her so much. Midget is trying to make friends with MY friends, and this kid who we were sitting with, well she ran over and grabbed him and brought him to HER table. It kills me how I can let a little midget walk all over me. She walks around, like a little five year old, with the baby fat and all. She's in basically all my classes you can say, and I want to make her so MAD. But I don't know how to get to her without being too tacky or outward. How can I RUIN her confidence? Please?