Hi Sue, I have had periods of this. Actually mine was hysterical laughter except it wasn’t funny… it was painful and scary and I couldn’t stop. It was before I was dx (or had any idea I had MS although I did have other early symptoms at that time) and it went on its own.
I’ve had it a few times since but never as bad and for never so long. Really thought I was losing my mind (as did other people at work etc. Was awful really and impossible to stop).
I wonder if an antidepressant might help simply because they do help with MS symptoms. Amitriptyline would be a good one to try (often prescribed for MS symptoms).
Take heart though… if mine is anything to go by it does go away.
I have read here and there that it can be a symptom of MS but I think other neurological conditions can cause it as well. You are right though, it’s not necessarily depression but something messing with part of the brain that controls emotional response.
Hope this helps. You have my sympathy as it’s distressing to feel so out of control.