Morning sickness?

I’m about 7w 3d. I’ve been taking meds for morning sickness since about 4.5weeks. I started with unisom and b6 at first and last week was started in a Zofran prescription. I felt yucky all week even on the Zofran. But Saturday I felt virtually fine and then yesterday I felt a little off but overall fine. Today I don’t even feel pregnant. Does Zofran take a few days to start working? Is me feeling good a result of the meds or should I be concerned? Only asking because I was on the same meds with both of my prior pregnancies and still felt sick with the meds so I’m not used to this. Also will mention that I had an ultrasound at 6 weeks 5 days and there was a heartbeat then.