I'm not saying you child is Bipolar or could be, but there is another good book, called Bipolar Child, written by a well known psychiatrist and researcher.

The night thing may be "night terrors"? 20 yrs ago our peditrician, explaned what night terrors are, she explaned how the brain growth development and body changes can cause this, so that is why the child may wake up,crying and then even screaming.
This was very scarey, we couldn't evn hold him, he'd cry, we'd ask him what do you want, we'd walk around the kitchen and family room, offering him anything, that may help him, he appeared to be wake but more like sleep walking, then he'd come out of it,I'd rock him to sleep as he cuddled up, then he'd fall back to sleep in his bed.
This only happened shortly after he'd fall asleep.
It stopped after a few months and things went well, before that when he was a newborn it was colic,after he'd pass gas that would stop.
Night terrors almost resemble that in the begining, but then escalate.
Oh as there are so many books,and different points of view, we did find one about night terrors that helped put us at ease, besides the pediatricians explanation.
Day time he was fine.
And like all our babies do, grow up and adjust, well I can't say that for all, that would be a generalization, for some can have problems, either physical,emotional or both.
I really feel for you and could imagine how difficult all of this is.
I've witnessed kids freaking out in stores, and couldn't understand why, or if the child wasn't being disciplined in some way, that's a hard thing too.
Most of the time it may be that the child needs a nap or a change in sleeping habits, just don't know.
Have you spoke to your pediatrician? Maybe they can suggest something?
Meanwhile, hang in there, for before you know it this shall pass.
But give the pediatrician a call, just to rule out anything before it gets worse.
Take good care,
DE