I had emotional extremes for a few years before I was diagnosed with MS. Laughing uncontrollably at times... and if we went to a funeral or visitation for someone else (not close to me personally) I would be crying more than anyone there. That happened twice so I stopped going to the funeral home unless it's somebody very close.

Soon after diagnosis I started taking antidepressants. I have to switch to a different one now and then if one stops working. I bet that's what's happening with you. Talk to your doctor and get a better/different AD.