Can a multivitamin cause a period to be longer and heavier with extreme dizziness?
NO, You may be low in iron(anemic),which would cause dizziness. Sometimes with loss of blood, especially prolonged loss, you lose a lot of iron. Try eating some red meat,broccoli, spinach,collard greens, kale, etc...or you could take an iron supplement or multi w/iron. Too much can be constipating so drink plenty of water.