DS age 7 with teenage sulky behaviour, help!

[SingleMum01]

My DS has always and is usually a sunny child. Lately when I ask him to do something he'll say 'no' - not all the time, just occasionally. Then he'll stomp about sulking and jut out his chin/lip. Is this just growing up (and it will get worse - aargh!) Where's my cuddly DS gone?!

What's the best way to handle it, just ignore it? I even go to another room (to calm myself down) and he follows me continuing the argument!

Right, I too have a sulky 7 year old. IT started with school actually and this smiley happy little boy disappeared. I think it was a combination of being tired, his father and I arguing and him finding school tough. He settled in at school and was happy again, he was very very popular. Not being a parent/adult pleaser (like ds2 who is very charming) I found it hard to believe he was such a hit with the children. I digress....
So after not doing so great at school we sent him to a private school where he was academically near the bottom of the pile and friendship starting again.
This year he's abck in a state school and he fits very well, he's in the middle academically and the weight of the world has been lifted from his shoulders. He still gets moody at times but generally a much brighter boy. I think year three is a real gear change too.