G said what I was going to say. Whilst N has his moments what you describe doesnt sound like him - the meltdowns, almost 'sabotahing' his own games etc. If I am giving him attention he doesnt get upset while we are playing or if something goes off course.
It isnt so new for you - you have these cycles - perhaps related to his sleep?
I agree with G why dont you get someone to check it out for you - it keeps coming up and I dont know how you deal with it all.
Like G - this all comes from our friendship and how much I care for you and your kids. x