Hello all, I just spotted this thread and have popped on as a 'been there' HG sufferer to give moral support and unmumsnetty hugs.
My sickness was pretty relentless from the start. I spent a few weeks with terrible indigestion on stomach pills (omeprazole) when I had no idea I was pregnant! Then one day the penny dropped and I ran for a testing kit. 
I was 8.3 when it all started to get silly, and 10.1 when I realised I was throwing blood up (Mallory-Weiss tear) and probably had HG (thanks to reading up on the net). Took self (with overnight bag) to A&E and after a few hours of drip, they said I wasn't leaving (as expected). I didn't expect to be ambulanced to another hospital at 3am, or to still be there a week later on the gynae ward! Off work another 5 weeks, then part-time as I eased myself back into being able to be there.
I was given cyclizine and ranitidine. I'd read about other, better drugs but needless to say my conservative PCT wasn't about to cough up for them. I was on them right to the very end.
By 18wk I was at last feeling like I could eat, and, after finding something that stopped me being sick (cheese ploughman's sandwiches, mayo, pickle and all!) I ended up carrying a boxful round at all times, even into meetings
. It worked, and gradually I started functioning properly.
Rest of the pregnancy was normal, up to 38.3 when the GP spotted the baby's heartbeat was in the wrong place, meaning breech. Off for scans and ELCS at 39.1, though that's a whole different story!
By then I was 40 (years not weeks!) and couldn't face the thought of having another bout of HG while looking after an extremely active and exhausting DS, so an only he will be.
I would say, do try and have calcium supplement tablets if you can keep them down. I didn't really eat anything for weeks (lost over a stone) and DS has hypoplastic teeth caused by not enough calcium when they were forming the enamel. We have to be very careful with toothbrushing and sweet things, and it shouldn't make any difference to adult teeth, but I do wish someone had told me at the time so I could at least have tried to take supplements.