I'm about 15 weeks pregnant and generally didn't have any major problems during the first trimester. I've felt a little sick here and there but the constant eating helped me from feeling really bad. Last morning on the tube, out of nowhere, I just started feeling weak and dizzy. I just couldn't stand on my feet and started sweating profusely. Everything was starting to become black for a few moments, and I just managed to squeeze out of the tube and get out in the air where I quickly recovered. It must have been low blood pressure and since I couldn't sit, that must have made things worse.
Has anyone experienced anything similar and how should I avoid it in the future?