Lahottie it's probably worth another try - it makes more sense that the medication might work better if your body is going to be more efficient at absorbing it, if you're hydrated then it might be easier. Have you tried Ondansetron? It's been recommended to me by the ladies on the Hyperemisis support thread, but my gp here (Belgium) won't prescribe it to me. It seems to be more widely known in the uk. Is that where you are? I took Chlorpromazine with dd, but the 20mg tablets knocked me out for hours. It was one way of getting through it, but with dd now being 16 months I can't risk falling asleep while looking after her. I too have tried pretty much everything in previous pregnancies, and whilst some things make it worse, chlorpromazine did take the edge off, and made it possible for me to eat and drink a little bit. I was still throwing up though.
How old is your ds btw? It's tough to be looking after a little one while so poorly!
Talking about going off food - I have been surviving for the last ten days on pita bread with Philadelphia. With dd I lived off chicken sandwiches for almost 4 months, so to anyone who's not able to eat much don't worry. The baby will take what it needs! Today has been awful nausea-wise. I managed to collect the kids and did a small and very slow trip to the supermarket but am knackered now. I was hoping that I wouldn't start vomiting for another few days at least, but I have my mouth clamped shut trying to keep it down
As soon as I have to speak I suspect I'll lose the battle 
Charlotte in case you're still reading the thread this pregnancy is natural, after having been told years ago that we would never be able to conceive again naturally. I had virtually no eggs left, and I have endometriosis. We thought having dd was amazing, but this just proves that miracles can and do happen.