blacked out at work

i’m 14w3d and i was at work earlier (i’m a cashier at walmart) and i was checking someone out and i started getting super hot and really light headed so i started to bend over the register bc i was scared that i was going to fall, and then i blacked out and the next thing i knew i was on the floor. i had just ate right before i went into work (i had only been there about an hour) and i had been drinking water this morning. does anyone know what could have caused this? and should i go to a clinic and get checked out or should i just wait till my next ob app? (it’s in 3 days) i tried calling my doctors office to ask them but they didn’t answer so i just wanted to see what you guys had to say until i could get ahold of them