It was a bit worse with dd2, vomiting a lot more and needing more hospital treatments for dehydration. It didn't last as long though thankfully!
dd1 I was sick from around 6 weeks- 25 weeks had about 5 weeks off then was sick again till the end.
dd2 I was sick before I knew I was pregnant (prompted me to take a test) that was before 4 weeks! Lasted till 23ish weeks, then I would just have random bad days here and there for the rest of my pregnancy!