Laila's Troubles

The other day I took Laila to her second Girlscout meeting. She was soooo excited to go, and kept changing her clothes all day trying to find the best outfit. She could hardly wait until 2:30.
When we got there, she did her cling-on-to-Mommy thing she always does in a crowd. We sat down on the carpet together and watched the other girls play rambunctiously on the floor. Then it was time to go outside and play on the playground for a bit while we waited for Laila's turn to be traced on a big piece of paper. She wouldn't play. Just watched from the sides whispering to me. So, I took her back inside to wait her turn for the tracing instead.
We had waited for the majority of girls to get traced, then make their way out into the hallway to color their self-portraits. I had Laila lay down on a piece of paper, and started tracing her. When I got to her ear, I accidentally pulled her hair with the pencil, and then it happened....tears started welling up in her eyes, and a little girl was standing there waiting her turn, but not watching, Laila freaked out. She jumped up into my arms, buried her head, and started sobbing uncontrollably. We sat there on the floor for about 10 minutes like this. She just kept whispering to me, "Mommy, take me home. I want to go home. I don't want to be here. Please, Mommy."
She is so debilitated by her shyness sometimes. It is really quite sad. It brought tears to my eyes even.
Since she was about 2, we have been trying to get her involved in groups to help her not be so shy around other kids. We started taking her to a UU fellowship when we lived in Michigan so she could be around other kids in the classes. She did okay sometimes there, but sometimes not. When we moved to Greenville, we did the same thing, going right away to the fellowship here. However, the teachers at the time, would not let me stay in the room for even one class, and she wouldn't go alone. So, we gave it up for a little while, until they sort of changed that rule. Then we went back, and she went for a while. She was okay and even enjoying it until one day in class, one of her friends, an older girl named Lilly did something mean to her (I could never figure out what, but I think it involved playing favorites with someone else), and she flat-out refused to go back. We tried for weeks and weeks to no avail to get her to go back in. Even when Lilly moved away, she still refused. So, we stopped going.
The homeschool group is fine, as they just play one-on-one mostly on the playground together. However, this Girlscout thing is not working out so well for her yet.
I really hope she can break out of her shell. I don't want to push her though and make it worse. I really am glad that I homeschool because forcing her into assimilating at school would be heart-breaking for both of us I think. I will keep trying with the Girlscouts for now.