Hope you get some relief Peanutbean - I can totally sympathise, half a stone lighter than I was this time last month! If you don't feel you have a good rapport with your doctor or you feel you're not being taken seriously, then you're entitled to a 2nd opinion by another GP. Have you got a midwife who you can talk to?
Popetteer - no, not a GP but a Hospice doctor - hence most of my patients will have nausea/vomiting issues at some point. Thankfully for everyone, pregnant women don't usually present to Hospices - so the only contact I've really had with pregnancy nausea/vomiting is with relatives of patients. I do feel quite impotent, curing other people's nausea and vomiting every day and being unable to do anything about my own nausea - as long as I can struggle into work, I'm going to try and avoid antiemetics - though if I did get really ill through not drinking/eating, I'd do something about it! In saying that, there are some women who have a horrific time with nausea/vomiting and need drugs/rehydration with intravenous fluids.
On the ginger biscuit etc front, I use ginger for some mild-moderate cases of nausea but have found that although it helped in my 1st couple of weeks, it does nothing now the nausea is worse. I also acupunctured myself for a while, and although it helped initially, it's stopped helping now.
Roll on the 2nd trimester!