Advice? Stay home. I fainted (literally hit the ground) twice in winco and a few times at school. I didn't have a car at the time so I HAD to shop cuz we had 0 groceries in the house. They brought me one of those motorized scooters (after failing can you believe it? Lol) soon as you get dizzy idc where you are sit down immediately. My bf got embarrassed a couple times till he noticed it was mandated. ALWAYS HAVE WATER/SNACKS ON YOU! Can't stress that enough. And I promise, it will pass. I know it's scary. I went to the emergency room twice and they pumped me with so many fluids for dehydration, so if it gets real bad, go in. You'll feel better when they're done.
I would call your doctor if I were you. It's either you moved too fast and got dizzy or it could be something else like blood pressure problems.