Dizzy at 16 weeks?

I had a stressful day at work today.  As hard as I try not get worked up, it's hard. (I work at a daycare...lol) I also didn't eat that well. Around dinner time I started to get light headed and dizzy. So I ate, drank some water. It's a few hours later and I'm still not feeling like myself. I could just be tired but I was just wondering if this has happened to anyone else. I have an appt on Friday and I will definitely bring it up.