Ah, welcome to puberty.....
First comes mood swings
Then hair in random places
Then more mood swings
These keep alternating until they are about 20 (so I am told)
Mine is 15 and I swear I didn't know boys got so moody. Ugh.
Also, with my son, sleeping a lot has always signaled a growth spurt.
I second the Ibuprofen - it will at least lessen any swelling in his gums and may make him feel better, hence reducing the moodiness.
As for the moodiness - I just point out to my son when he is being particularly sullen so he can learn to adjust his attitude. Sometimes it works, sometimes I just send him to another room. :) It may be time for the "when your body matures" talk to begin explaining the changes that will happen and give him a road map to help him navigate through this.