Ok so does this happen to anyone else... I'm 18wks tomorrow but lately I've noticed while walking…

Ok so does this happen to anyone else... I'm 18wks tomorrow but lately I've noticed while walking around any store for a long period of time with nothing to lean on I seem to get short of breath and become nauseous. I tend to have to squat or lean on something but try to make my trips in the store go a lot faster once I start to feel this way.