How can I help my 6 y/o get over her anxiety?

  I think AdviceMamma's reply is a good response.

The only thing I might also suggest is perhaps "Play school" at home with your daughter. Play out different typical daily activities that occur in school.

   One possible fear she my be having is not doing things right".  

I have found some children have high expectations of them selves.

They are afraid of giving "wrong" answers, completing activities that aren't up to "their".standards In other words, a perfectionist. 

  For this, time and confidence will need to be given with guiding hand.

I would also inform your daughter's teacher of her anxiety and discuss ways to help work through this.                  

Some children embrace change, eagerly anticipating life's next new adventure, while others cower in the shadows, hoping that whatever new experience is waiting will just "go away." Clearly, you have a child in the latter category!

When a child is upset, imagine that they're in the midst of an emotional storm. In that moment, it's as if your daughter's belly has a swirling mass of feeling that's flipping and flopping in her tummy, causing her to feel an almost primal, survival-related fear. It doesn't make sense that something so relatively harmless -- and potentially fun -- could have such a big effect on her, but that's how it is for children (and adults) who suffer from anxiety.

Trying to calm her down with positive thoughts in the thick of that emotional mayhem would be a bit like trying to hang pictures on the wall in the middle of a hurricane.

Rather than trying to get your daughter to relax before she heads off to do something that terrifies her, I suggest you desensitize her to these new experiences ahead of time so she can gradually ease her way into becoming comfortable, without feeling overwhelmed by all the new children, teachers, rules, play area, smells and sounds.

Take her to the nursery school, kindergarten classroom or camp venue at least a few times before she begins attending so she can wander around when it's quiet (and later, when there are children attending) so she can get to know the room, playground, and staff. Ask her teachers' help in forging a connection with your daughter -- perhaps even having lunch together, or going for an ice cream -- so she can begin to develop an attachment without the stimulation and distraction of lots of other children competing for their attention.

One calming trick you can teach her is something I call Bear Belly Breathing. Have her lay down and put one of her stuffed animals on her tummy, and ask her to make the little animal rise and fall as she breathes in and out. This deep breathing will help her relax and get out of the "storm" of those wild emotions that descend upon her when she starts feeling anxious.

If you ask your daughter to tell you why she's anxious, and focus on using logic to convince her that there's nothing to be afraid of, you won't get very far. (I think you've discovered that!) Instead, be that captain of the ship that recognizes that your daughter is wired to be more sensitive to change, and work with her to develop the skill of adapting to new experiences.

Yours in parenting support,
AdviceMama