Dizzy, Lightheaded, Ears Ringing..

Yesterday I got really hot, to the point I was sweating. I then got really dizzy and light headed and I had to walk in my house and I barely made it without falling down. It was almost like I was drunk. Then I got where I barely could hear anything but a constant ringing in my ears. It was really scary. I'm 16 years old, and I'm 11w3d pregnant. I went to the doctor last week and my blood pressure was fine, everything looked normal. What could this be? have you other pregnant ladies gone threw this?