I'm in my later 20s, but I've had problems during the summer since my later teens. One of my ways of compensating was to go into education, where I'd be on furlough from work during my worst months. As far as crying during a shutdown--I do it, but it is a rare thing for me. I have to be shut down to the point of attempting self-injurious behaviors before I start to cry. I am not sure why, but I think it is because when I was young, my father would shake me and scream at me whenever I started to shut down. He always mistook the breakdown/shutdown for "throwing a tantrum to get what I want".
I hope things go better for you soon. For me, once we get to the point where the days are under 85 degrees and the humidity goes down, I find it much easier to focus.
Best Wishes,
MMonjeJr