Thrush? or what does this sound like?

My daughter has been really fussy the past few days. We took her to the doctor and he said he noticed nothing wrong in the physical exam and that if he could put a name on it it would be colic. Im not saying that he is wrong, but just now my daughter spit her pacifier out and I noticed on the roof of her mouth a little bit of white like where her teeth will come in on her gums. I think that maybe the doc could have over looked it. Does this sound like thrush? If so, what should I do?