Dizzy, dizzy, dizzy

I'm almost 7 weeks into my first pregnancy, and I can't stand for longer than 5 minutes without getting really dizzy. Like I was making a salad for lunch a few minutes ago, and I got so dizzy I had to sit down with my head between my knees. I'm drinking about 3 bottles of water a day, plus juice and ginger ale (for the nausea). I'm eating as well as I can. I'm taking my vitamins. What can I do to stop the dizzy spells? I have my first ObGyn appointment in 2 weeks (I just found out I'm pregnant a few days ago, and the 21st was the first available appointment). But what can I do until then?