I know this answer is far too late, but since you had no replies:
It sounds like it could be related to panic attacks, even if many of the symptoms were missing. You could do internet search for "pregnancy panic attack" to find reports by women who began having attacks while pregnant. Maybe not the same as what you had, but it could be related. The brain and body are very complicated, and as I understand it different pregnancies can have different chemistries to a degree because each child has unique genetics and thus a unique interaction with the mother, unique nutritional needs and so on.
Here's a link to someone who describes the sensation of silent screaming and crying in their mind during panic attacks, but of course this is different from what you experienced. Just hoping to provide clues:
As far as health and nutrition are concerned, and how they relate to the mind (and could relate to your problem), you might like to read "The Ultramind Solution" by Mark Hyman. He writes in a bit of a sales-pitch-y way, but he does a great job of making some powerful, cutting edge health information available that many doctors have not learned about yet.
As always, please use your own discretion regarding my suggestions. I have no credentials, and it's healthy to apply a bit of skepticism anyway even when someone DOES have them. :)
Anyway, I hope you have not had too many problems and your pregnancy is going well. Best wishes to you and the baby! ;)