Morning sickness clearing up at 9 weeks?

I've had pretty consistent nausea since 6 weeks but the past couple of days it's seemed to get better...and today I really don't feel anything. Is it normal for it to get better at this point? I always thought it lasted throughout the first trimester at least. I have a home Doppler and heard the baby's heartbeat today so I'm assuming all is well...just seems strange to me?