Sparkly1,
I'm on the Due in Sept' thread and a couple of us are second time round hg (hyperemesis gravidarum = excessive vomitting in pregnancy) sufferers who have both had a trip or more to hospital both times.
If you are being sick more than 3 times a day for more than 3 days then GP's are supposed to take it seriously but in our experience they don't, nor do their busybody receptionists nor do midwives.
I was taking anti-sickness drugs from week 5 and asked to be monitored this time but they said,"Oh no, need you'll just know when it's time to go into hospital for rehydration fluids and anti-sickness drugs"
After being in hospital this time I realised that they measure the ketones in your urine to determine what state you are in. You can buy Keto-sticks from your pharmacist and this will give you an idea of when you are in ketosis from the dehydration/vomitting and this can then be pointed out to your GP when you see them.
If you get pretty weak I would recommend that you bypass the GP route altogether (as they may only prescribe less effective drugs such as stemetil or phenergen which few people with hg have found effective in my experience) and go straight to A & E. Have your husband/partner describe how bad you are as it seems to carry more weight if said by the opposite sex.
If you are admitted, do not let the ward discharge you until you are eating properly and get a take home prescription of anti-sickness drugs. Also, if your bowels have ground to a halt due to lack of food passing through, ensure that you get prescribed a stool-softener as piles can result from the effort required to get things re-started at the bottom end.
Sorry if this is scary or too graphic but I was horrified to end up in hospital the first time round due to being ignored by three GP'S and a community midwife. Second time around I kind of accepted it as inevitable and didn't find it scary at all, just disappointing.
Pop over to the Sept thread and ask Homemama or I anything you want about the subject if you need to. (Homemama has hg much worse than me as it varies in its degree)