Dizziness on 20 weeks

At first, I thought I was just about to vomit. Then comes my head, getting heavy and my sight getting fuzzy. I am lucky I was able to hold unto my colleague tight and with the other students, they assisted me to sit. I had my breakfast, I drank water even before I left the room, was feeling well, but not until minutes ago. I had a lot of sweat. Sitting, I closed my eyes as one student put a menthol liquid on my forehead and made me sniff it after, and my colleague holding the fan for air. This was a first time for me. I never had this since childhood. I always considered myself physically strong. Made me think: Am I missing something? #pregnancy #thirdchild #20WeeksAnd5Days