Weird feeling. Please help

Melissa • 26. I love my husband and so thankful for my friends & family. We're expecting our first little one.
 I keep having these weird "episodes" where I get a hot flash, feel all dizzy and light-headed, my ears ring and my vision gets blurry.  I have had them both up and moving around and also just sitting and it comes suddenly.  I'm not sure what's going on. I'm 24 weeks pregnant. 

 Went to a general Doctor and he said everything seems fine. Blood pressure and sugar are good. And I can still feel the baby moving a lot.

 Anyone have anything similar? I'm mainly wondering if anyone had the kind of hot, dizzy, faint feelings episodes I described above.

 Any thoughts are appreciated!