Sorry if my response is not what you hoped to hear.
With my first (DS) I was severely ill from 6 to 12 weeks, spent the entire time hospitalised and on a drip. Maxalon did not help and I was offered nothing else. At 12 weeks I suddenly felt fine and had no nausea the remaining of my pregnancy.
I am now pregnant with my second, a girl, and am now at 20 weeks still vomiting every morning and taking zofran. Without the medication I spend the entire day wrapped around the toilet bowl, but with it I vomit once in the morning and then feel nauseous but no vomiting for the remainder of the day.
My midwife said from her experience it gets worse in subsequent pregnancies.