Right, so you're not carrying extra weight to start with. 5'5" and under 9 stone is definitely below the uk average ;)
Your level of nausea isn't normal - and you don't have to suffer with it ! You need to get over to the hyperemesis support threads, they are fabulous.
Then, tomorrow, book an apt with your GP. You need to let them know that you're not keeping down food and fluids and you want medication. They may try to fob you off with the whole "sickness is normal in pregnancy" stuff. Don't listen - it is not normal to be sick all day every day for weeks on end and there ARE medications that are safe in pregnancy. It is NOT true that there's nothing they can give you.
Hopefully they'll give you something. If not, the ladies on the hg threads will have advise.
Then you need to address trying to get some food into you. Firstly, go get some prenatal vitamins and take them. If you can't keep them down, try a liquid tonic like spatone or floradix. Try taking them at night as well, that can help, or when're you feel least sick. I can't take extra iron so I make do with a half a berocca.
Try to get calories and nutrients into you any way you can. You might want to try:
Smoothies - you can sip them gradually over an hour or so
A bit more oil/cream etc in food.
Very finely cut up fruit - at one point, wafer thin apple slices kept me going. Fruit seemed to be ok where anything else triggered sickness.
Get others to cook for you
Small portions - nibble little and often
Pre prepared foods - means you don't have to cook.
Fortified breakfast cereals - most cereals have vitamins in
Fluids! Very, very important - if you can't keep them down, get a teaspoon, and take a teaspoon of liquid every few minutes. If you're dehydrated, it's very important you seek medical help.
Good luck - you absolutely have to get some help and get this sorted.