Definitely trust your gut. I knew something wasn't quite right with my little girl very early on (I can't remember specifically but it was probably around the 6 month mark), and was repeatedly told by anyone and everyone that she was fine. It wasn't until I finally broke down in my own GP's office when she was almost 2 that somebody took me seriously and genuinely listened to my concerns. Its great that we finally got her the help she needed, but it makes me very sad that it could have come earlier if I had just dug my heels in even more than I already was - even my DH didn't think there was an issue for ages.

If you think something's not qutie right, then get it investigated and if you're still not happy with the results, get another opinion until you are satisfied. The worst that's going to happen is you're going to happen is that you will end up with a "normal" child.