On the first day of the 15th week - so maybe not long! But I didn't tell any of the docs (I was in hospital) for 3 days as I wanted to be sure before thet discharged me (I was in and out 4 times with HG).
Hope you feel better soon. DS is 18 days old, everyone said that the baby would make me forget all the sickness - but no, I still remember it vividly!
It got better in that I could move about a bit (at it's worst, I was bedridden and suffering constantly!). I was able to buy baby stuff later on in the pg, but my mum went with me as I was too ill to go alone!
I was sick right up to delivery, but I had quite a few phases where it wasn't quite so bad (ie throwing up just a couple of times a day instead of constantly), and those phases lasted a week or so at a time, scattered throughout my pg. But my sister who had HG too was better by 17weeks with both of her pregnancies, and I think that's more common. Sympathies, HG is so horrible.