Ok, now Im really confused about the growling!

[picnicinthewoods]

I have been worried at my 16 week old puppys growling, but decided to give him the benefit of the doubt since hes had an upset tummy (with blood) and also has only been with us 2 weeks. Growling started on about day 2.
We are going to puppy training next week, so will get more advice then and are also having a one off session with a behaviourist. However, since the panic, Im now really confused as he growls at everything!
He growls when hes happy and excited (say when we come home from popping out), I know hes happy cos his tail is wagging!
He growled at the x-factor (but quite frankly I think that's allowed!!). He growls and barks if my DD wears her tap outfit or weirdly, her Brownie outfit.
He growled today when he could see the trees outside blowing in the wind.
He growled at my husband when he took his glasses off.
He growls when you play with him (again tail is wagging).
He growls when hes frightened and hides behind me.
He growls when hes trying to rest and he wants the kids to go away!
He is a very submissive dog, rolls over to be stroked, is very timid and shy. He is also an excellent communicator.
So in short, is this normal?????!!!!!

IAmNotAMindReader, thanks, that's music to my ears! I'll check out some breed specific sites. I'm currently writing down every time he growls, coupled with body language to try to get to know what he's trying to say:)

Picnic, seems quite good for learning the basics of canine body language. I've only watched the first one so far but the info seems sound enough and it has video and images of dog body language within it, that are talked through to explain their meaning.

Those videos are brilliant moosemama, Ive just watched the first 3. Very interesting, especially the eye contact thing and what she says about growling obviously. So change of pitch when growling is talking & continuous pitch growl is warning. He had done both types. Thanks, very helpful.