Rebecca, I'm sure you're just trying to be funny, but I doubt the OP is laughing when she feels like hell and is trying to get some support. Not particularly helpful to be taking the piss.....
OP, sympathies to you. I'm on my first HG pregnancy and have no idea how anyone copes with older children on top.
Have you come across Pregnancy Sickness Support? This is a great website and the helpline is really useful. They can give you the details of a local HG friendly consultant if your GP isn't doing enough to help
www.pregnancysicknesssupport.org.uk
You should go back to your GP and say the drugs aren't working. Please ask about ondansetron. It's the most effective drug out there and has helped lots of women. It can be hard to get it prescribed, so here are the official guidelines if your GP gets argumentative. I couldn't have got through without ondansetron - not a magic bullet but definitely helped. However ask for something to counteract the constipation.
www.rcog.org.uk/globalassets/documents/guidelines/gtg_57.pdf
I know your scared to drink, but if you don't try to stay hydrated, you'll end up in hospital on a drip. Some people find sugary drinksstay down easier than water - try flat Coke, lemonade, juice from tinned fruit. Personally I found sipping Lucosade helped a bit. You can also try liquids food to stay hydrated like soup and jelly, or maybe fruit?
Regarding food, nibbling tiny amounts of bland salty carbs worked for me - toast, instant noodles, mash and gravy, salted crackers, digestives. However some women find high protein works instead.
Otherwise, all you can do is rest as much as possible. Draft in family and friends to help care for the older kids if possible, otherwise can you pay for extra childcare? If not, some extra tv to keep them quiet for a bit won't do any harm. Fingers crossed yours might calm down towards the end of the first trimester, although some don't feel better until 20-ish weeks or even throughout the whole pregnancy. How long did your HG last in previous pregnancies?
For ranting and support, please join us here
www.mumsnet.com/Talk/pregnancy/3030649-Hyperemesis-Support