I had felt the same way and found out I was very anemic and had to be on b12 complex shots my reg vitamin and b12 pills and I make sure I eat n drink enuf n its went away
I am also due in April (24+6 wks) and I know exactly what you are talking about. Right before Christmas I went to the mall and was so close to fainting that everything around me got quiet for a second and I was sweating all over, dizzy, feeling like I was gonna puke.. And it wasn't like I had low blood sugar because I had left a breakfast diner right beforehand. It's not always hypoglycemia like some people believe, I don't because I've been there. Seriously I know in my heart it wasn't a panic attack although some would blame that also. I think honestly its just hormones (generic answer), changes in blood pressure/flow, and God only knows. I didn't even want to drive or go out alone after that happened. But as long as it isn't a constant thing try not to get too worked up, because it isn't completely uncommon for it to happen. But it is frightening to lose control of your body.