I had this happen to me right around the same time- it was awful! I totally feel your pain. I talked to my OB about it, and he said it happens because that's right when your uterus is reaching your diaphragm, and the pressure throws off your balance, etc. and causes the dizzy/nauseous feeling. (I had always thought that it was the inner ear, but apparently the diaphragm does it, too). I got seabands, which did help some, but, mostly it was just time that helped. By the time I was 30-32 weeks, I felt so much better, I think that my body just got used to things being squished. It was awful toughing it out for those few weeks, but I just made sure I always had a little water bottle with me and got off metro for a few minutes if it got really bad. Thank goodness it finally went away. Hang in there!