Is it normal to faint

I'm 8 weeks pregnant, and this morning I fainted when I got out of the shower. Hubby took me to bed where I lay down for a few mins till I felt better, then I ate my breakfast and got ready for work. Then I fainted on the bus too :( I was standing up in the aisle and went over all hot and funny feeling, so undid my coat then my vision started blurring and I could feel I was going to faint so I pushed thru the people (they must have thought I was so rude) and plonked myself down on the steps and started sweating and being all cold and clammy and shaky - it was really scary. I haven't fainted since I had stitches take out of my feet 3 years ago. Is this because of being pregnant?