8 wks preg. w/ second child, no morning sickness...?

When my first child was conceived, I was barfing my head off before I had even missed my period, and as I was told is typical, it diminished shortly after I entered my second trimester. Here I am now, 8 weeks along with my second pregnancy, and I haven't experienced a single bout of nausea. Is it normal to have such variation between pregnancies? Thanks :)