She sounds alot like DD1 at her age, i can tell you it does get better (in ways, but then other things drive you nuts)
could have alot to do with having younger siblings to i think.
with DD1 i thought 2 was a bad year, then we hit 3 and that was worse, then 4 came along and OMG i was ready to adopt her out!! but at 5 she's probably as annoying and naughty as she was when she was 3.
Hope the doc can put your mind at ease hun xxx