Crying and overwhelmed for no reason?

I’m 16 weeks pregnant and, since entering the 2nd trimester, I find from time-to-time I just feel teary and for no reason. It’s usually overwhelming tears, and I don’t know why.

As someone who is pretty tough in most of my worlds, this feels highly unusual and so foreign to me and I just want to know why. My baby is fine, work is fine, husband is fine - so what’s wrong! It’s hard for me to explain to my husband other than to say it feels like panic but not because of any particular reason which sounds crazy.

Had anyone else experienced this?