I never had nausea like this with my first, either. This kind of morning sickness took me completely by surprise and knocked me right on my azz. I would say that the all day hangover/puking stopped around 11 weeks. The waves of nausea and exhaustion has let up in the last week (13 weeks). I still don't feel great, but I can make dinner, keep up with DD, and get stuff done around the house now.
Hope you start feeling better soon.