Remember the "Terrible Twos", when they went from sweet baby to ruler of the world? Well, here they are again! This to shall pass, put on your "extra patience" hat, and try not to take everything he says too litterally. Just like you did when he was two, it is time to set limits. Give him a timeline (this helps for everything this senior year) when something needs to be accomplished and set whatever consequence you decide ( can't go out, can't drive car, etc.)and enforce it.
Senior year it seems like it is a constant uphill battle until all the college aps completed and deadlines have been met. Mine kind of went in and out of this mode until he left for college in August. But it definately got better once he knew where he was going.
They are going through a lot - I am sure when asked, your son could not articulate why he is feeling sensitive or moody, he just is.
My son had proven to me up to this point in his life that he was deserving of my help to get him through it. So, I did help him out by setting the timelines and making him stick to them. I personally called his counselor/advisor and set up a time for him to bring in his essay for review and edit, and I made him go. I would have gladly done it, but he needed someone else involved to we didn't need to bicker back and forth about it.
This worked out well for us.
Try to bite your tongue as much as possible, choose your battles (just like those terrible twos).
I have found in parenting that everytime an uncomfortable period arrises it is almost always followed by a big step toward maturity.
So, hang in there and dish out big chunks of unconditional love (even tho you might not feel like it)it will get better. Best of all you will know it is coming with your other kids, the first one gets to suprise you with all of this
Hope that helps.