Is she aware, of what is going on during these attacks? Can you talk to her or does she appear non-responsive. If so perhaps she has seizures. You can get her tested for that by going to a neurologist. They can do an electroencephalogram or EEG. They will probably do other physical exam too. But for the EEG it doesn't hurt at all and they put wires on the head and test for the electrical part of the brain to see if there is too high of brain wave activity. If she does have it they can control it with different medicines. They might also want to get a CT of the brain to make sure there is nothing wrong there. But it sounds like a seizure. They can happen frequently, especially in children. You should get her in as soon as possible with an neurologist. If they can't get her in see a GP and they can have one ordered for you. Another thing to think about is does she have a high fever? If she does then I would take her to the ER because she could have meningitis. Otherwise, she is ok to wait.
Mandle, how old is your daughter, and can you explain further?
When you say she feels really sick but never is actually sick, what does that mean? Does that mean she doesn't vomit, or does that mean she doesn't run a fever or show other symptoms of illness?