anybody else feel faint when standing for a long time?

Nicole
Every time I stand for a longish period of time, such as taking a shower or browsing in the store, I suddenly get sweaty, dizzy, nauseous, see spots in my eyes, and have the feeling that I'm going to pass out. This makes me have to sit on the floor for a bit if I'm out in public, and it's super annoying. I'm 31 weeks. Is this normal? Has anybody experienced this?