Should I be worried?

Stephanie • Boyfriend: 12/29/2014 - Forever :) Baby Boy - 09/25/2016 and pregnant with baby #2 due 11/20/2017

So I started a new job yesterday. In under an hour, I had 5 or 6 heat flashes and I had to sit down for two of them or I would have fainted. I drink SO much water and splashed my face as well but nothing was helping. All I did was scan and label boxes, then put them on a cart behind me. And the boxes are light so I don't think it was from that. Should I be worried? Also I'm 24 weeks pregnant.