Symptoms have gotten better...is this normal?

I'm just over 9 weeks along and the past couple of days my symptoms have gotten better. I've had terrible nausea for the past 3-4 weeks but now I barely feel anything. Is this normal? I heard the baby's heartbeat on an at home Doppler today so I think things are fine...just finding it strange that my symptoms have almost gone away. Has anyone else experienced this?