M.C.
My daughter did this too. I'd have to put the TV on really loud to "snap her out of it" and then calm her down. I thought maybe she was feeling uncomfortable from something, and often times she was gassy and after that passed, she would calm down. I stopped giving her milk before bedtime and it really helped a lot. It was hard the first couple of nights and still months later she will occasionally ask for milk at bedtime, but it was worth it. Her screaming really eased and now when she cries at night, she can soothe herself back to sleep.