HI B.!
Congratulations on motherhood!
I began having episodes of vertigo at the end of my pregnancy with my youngest. My vertigo was to the point of vomiting, though :o( I learned how NOT to tilt my head in the shower, how NOT to rotate laundry, etc.... all to try not to "set it off".
The Dr never found any trouble with me. I eventually found that it seemed to be associated with allergies! I couldn't feel the allergies bothering me, but once the vertigo began it all pointed to allergies (plugged ears,slight stuffy nose). Nothing really took the symptoms away completely, but Dramadine helped ease the nausea. Tylenol Sinus seemed to help reduce the "episodes" of dizziness.
I basically just learned how to move around without instigating the vertigo.
Today, my youngest is 6, and I still occassionally get vertigo. My case seems mild, and I'm just getting better with avoiding the problem.
I know it's miserable, but you will find a way to work through it. Just try to figure what "triggers" the dizziness (eg: mine was each time my head layed to the right, or moved my head too fast) and be careful with that baby!
I hope some of my experience helps to understand your situation a little bit better.
~N. :O)