Sudden blackout?

I’m 16 weeks pregnant. I was outside today when suddenly, out of nowhere I got super hot and sweaty, dizzy and lost my vision completely. Had to sit down in the grass. It went away shortly after and then I threw up when I got back on my feet. Went inside to lay down and now i feel fine. I haven’t had that happen ever until today. Anyone know the reason? Drop in blood pressure maybe?