I remembered Pseudobulbar effect

Yeah, I'm very similar to you in that I'm most often quite cheerful and happy but every once in a while, have tears for no reason. Also happens with laughter. For me it seems to be a hormonal imbalance thing. I just started using essential oils for balance and it seems to be helping. XX

There's a name for this, pseudo something, but it is due to the lesions being in the part of your brain that controls emotions. My friend cries over every thing, even when she's not sad.

I think it's more a matter of your brain giving itself an emotional balance, I was the complete opposite, during my darkest days I cried half the day, every day, for over 6 months and was so emotionally weak. By the end of that period I no longer wanted to cry and had gained mental strength as a result of purely surviving all my traumas of that moment. It's been 2 years since I cried now and it'll be a cold day in hell before I cry about my MS situation now, I have fight in me because of where I've been in life, you're a fighter too, it's a blip.

Depression, anxiety and grief are logical results of any chronic, progressive illness. Not everyone will experience all of those an some will experience the symptoms repeatedly. When there are changes in symptoms, as there often are with MS, mood symptoms occur.
Talk with others who deal with the same thing, talk with family, friends, exercise do things you enjoy