Should I move classes for this?

Well this year in my class I only got one person I knew because we're in the same group of friends at lunchtime although we never really talked much. So we sat next to each other and this other girl also sat with us. So us three all sat together and then I noticed them two always being partners and leaving me out a bit. I got really jealous and then at the start of term 2, a new girl came. I talked to her and sat with her and she was really nice. But then she became closer friends with the others than me. The girl who hangs around with the same friends as me did want to sit next to me anymore. So I always had to sit at the end. I was a bit jealous, but I could live with it. Then about two weeks later, another new girl came. She wasn't as approachable as the other girl but I still decided to go and talk to her. Then whenever I tried to sit next to her, she said that one of the others was sitting there and even if they're not, she makes up these dumb excuses like it's too hot and stuffy in that seat. So the others became friends with her, and I was the only one she was being mean to. She always asks me embarrassing and nosy questions, like "why does your face always turn red?" and "why is you writing so messy?" and she called my friends (in another class) weird. And she's so bossy. But they all like her. I feel really left out and don't feel like I belong with them. I just hated them all for some reason. And now I feel really nervous and too shy to talk to the others. They think I'm weird and boring and never want to sit with me. I can't live with this- being asked lots of embarrassing questions, sitting by myself, always being left out, being put down by them. I was thinking of asking the teacher if I could move classes. I would be able to concentrate on my work more and work better in groups. Should I do this? The problem is everyone from both classes will ask why I moved and theres a few people in my class I'll miss. Am I being a coward for taking the easy way out?