M.L.
My daughter turns 7 next month, is in first grade and does EXACTLY what your daughter is doing. Sophia has had some OCD issues for several years (repeating I'm sorry, hand washing, etc) and she has anxiety (unreasonable fears like what if the store closes while we are here, etc. She is a very kind and loving child in part because she is always worrying about other children.
She is a twin which makes it even harder because if I compliment her sister she and not her then I don't love her.
I don't have much advice, just commisserating and telling your our story :)
Sophia has been seeing a psychologist since June.I am not seeing as much progress as I would hope but what I have seen is that by having an adult ask her more probing questions she is much more aware of her feelings and able to communicate them than other girls her age. I am hoping that as she matures she will be able to learn more coping skills.
I can tell already that my girls blow off what I say because I'm "just their mother". One of the things the psycologist said is to find something she enjoys. She doesn't have to be good at it, just enjoy it. For her that is writting songs, poems, stories.
You can't just say "your beautiful". You have to say "you were very nice when you shared your toys" "you wrote very neatly on your paper" etc. She says "Do you still love me". Of course I say "I will always love you no matter what". But, I think she gets the message more when my husband or I argue and she says "do you still love dad?" and I ask "do you still love your sister when you fight?". She knows she does so that helps her to learn that you can have conflict, resolve it and still love each other through it all.
She says "I don't like being fat". I used to say, you aren't fat but that didn't work. Now I tell her mom is bigger than the other moms, her dad is taller than the other dads so she will probably be bigger than the other kids. she doesn't like it but I am hoping she will accept it.
Sorry I'm rambling. I feel your pain. I wish I could just give her a happy pill to take away all her worries and fears but I can't.
Another thing we talk a lot about is CHOOSING your friends. My daughter is always drawn to the kids who want to shun her. We talk about who is kind or makes her feel good about herself. She says "I don't want to hurt their feelings" (that's the girls who are mean to her). So, we talk even more ;) about how she shouldn't exclude kids but she can pick who she jumps rope with at recess.
Good luck!!!!