Fainting spells?

Anyone experience fainting spells in the 3rd trimester?

Mine start with dizziness and lightheadedness, then cold sweats- like dripping sweat, and I feel like I can't breath. I just sit and keep my legs moving to avoid passing out. Also I get a strong crap I'm gonna throw up feeling. I'm not dehydrated or anemic. I've eaten, so it's not that. Anyone else experience this?