Starting near the end of the 2nd trimester I started crying a lot some days... and once I start I can't stop! It seems to be mostly over silly things, although if I really think about it there's almost always something deeper underneath what seems trivial.
(For example: Someone parked in front of my walkway and has been there for FOUR DAYS... I cried when I saw they hadn't moved their car today. I leave in the mornings in the dark and it's starting to get icy, so I don't like walking further than I have to because my balance is usually fairly 'off' in the mornings. When I really thought about it I think on some deep level I'm not feeling very welcome in my new neighborhood when people seem to continue to park in front of my house blocking the walkway even though they can see I'm hugely pregnant and it's a pain for me to get around without that walkway)
Normal pregnancy hormones? It does feel an awful lot like hormones, and reminds me of when I'd cry before my period when everything just seemed so HUGE and daunting.