Morning sickness at 20 weeks?

Erin
Even in my first trimester, I rarely vomited. I was nauseous a lot, but usually only vomited if I was brushing my teeth (damn gag reflex). Now, at 20 weeks, I have puked once every morning for about the past week. Doesn't seem to matter if I've eaten first or not, or what I've eaten - just spontaneous, then it's gone as soon as it happens. This happening to anyone else? This is my first, so not sure what's normal or not. Have to call my Dr. today for something else, so was going to mention to him, but curious as to whether I'm alone here.