With my first I threw up almost every day until I had her out at 36 weeks. I still managed to put on 4 stone so you can imagine how much I was eating.
With this one I was very sick for the first 16 weeks and lost a stone but have continued to be sick once a day (usually dinner, not the whole meal -- it's like my stomach can't contain that much food) and although I have slowly regained the stone (am happy I weigh the same as when I started, believe me) and baby is fine etc.
I'm so used to it and it doesn't bother me so much (don't feel constant nausea) but I don't know anyone else who has had this. Plus I hate having to bundle loads of bog roll in my knickers when I'm sick (TMI, but a particularly violent hurl and a weakened bladder, you get the picture).