My son had many of these similiarities as well. Developmentally (as a baby) he was fine . . . but around this same age (he is now 5) he would pretend play, have lengthy conversations with himself when playing with his toys. But, he never took an interest in learning activities, like sitting to learn his ABC's or counting. He would just eventually come to me and say "mom this truck is blue." He was very social though, not necessarily with children, but with adults. It often scared me at times as he would speak to anyone. He would often walk away from me in the stores. When he entered preschool at 4, he became a disturbance to his class, would not listen, would laugh at the teachers when he was being punished. His behavoir wasn't much better at home. We had a difficult time controlling him. Eventually, he was kicked out of preschool and I took him to a child psychiatrist to be evaluated for ADHD, ADD or bipolar disorder. That dr told me he had none of those things. It was recommended that I continue to keep his punishments consistent. When he entered Kindergarten a few months later, I was constantly receiving phone calls from the principal regarding these same behavoirs. They suggested he had ADHD. He was tested by his pediatrician in November of 2008 and does have ADHD. My son is also below his grade level due to the concentration level that he has - wish is none.
My recommendation is to just watch your daughter and see how far the hyper activities go. She may calm down. In my experience, my son didn't calm down, he got worse.
Hope this helps.
Hit the breaks!
Your daughter is 3.5 years old.
Every 3.5 year old is constantly "on the go" and is constantly "chattering."
Do not let a grade school teacher's unprofessional diagnosis of your daughter's mental state have any effect over the way you see your child. As soon as somebody says something like that, every little thing your daughter does is going to seem like a symptom of anxiety or ADD to you.
If you are worried about this the last thing you want is the opinions of people on a message board adding to it.
Your pediatrician should be able to answer all the questions you have about these things. And if you are really worried, could refer you to a child psychologist.
At the very least, I would suggest posting your question on the "Ask A Doctor" side of the forum.