I had the same thing around the same weeks. Very similar story I would stand for awhile but not doing heavy work either. I did get a gestational diabetes test done & everything was perfect. It happened about 6 times at work before my Dr made me stop working. He said there wasn't really anything more serious other than standing for a long period of time. It cause your blood pressure to drop drastically which is why you suddenly start sweating & get really dizzy. Best advice is to try to move around every ten mins if possible. Go outside catch some air come back and you should be fine. Personally I couldn't handle it, nothing worked for me so I had to leave my job temporarily until my baby is born.
I hope all goes well. Please let us know i have the same thing only i havnt told anyone :/
Thanks, I hope so too! Didn't have this with my 1st child.
I had this with my first around about the same time 19-21wks. It was just dehydration and not eating little regular snacks enough. Fingers crossed its something simple for you too.