Hi NorthLondon, I’m in a similar position to you. Pregnant with DC3 and first time with hyperemesis. Didn’t have an amazing time with DC1 and DC2 - had all day nausea and occasional vomiting - however I could still manage it, I just felt a bit rubbish, so I could still go to work, do household tasks etc. This time has totally thrown me, I honestly had no idea I could get hyperemesis, I assumed if you got it you had it in all pregnancies. Like eallison says, if you’re not on meds already then do speak with your doctor ASAP. I’m on cyclizine, first week on it knocked me out a bit, was super drowsy and didn’t know how I could possibly continue with it, but stick it out - within a week I was back to my (relative) normal, drowsiness-wise.
FWIW it hasn’t made my illness disappear but it did hugely reduce the vomiting and retching and helped me to start eating and drinking more, which makes a big difference to your physical health as it makes it less likely that you’ll become dehydrated and such. One thing a lot of us here have agreed on is that one of the challenges is actually significantly lowering your expectations of what you can and can’t do. Like in a lot of recent posts, physical exertion is a common trigger for feeling worse, but we’re not talking about going for a run or cleaning the whole house - even simple tasks, like loading a washing machine, putting away dishes or simply talking can be a bit too much. It also usually takes longer for the symptoms to lift, so whereas in normal morning sickness you should feel much better by the end of the first trimester, for many women with HG it starts to improve by/around 20 weeks, although some continue to feel a bit off (but manageable) and unfortunately for some they continue to be ill.
Are you at home with the DCs? Are you able to take it easy? I’ll be honest, at first it really is tough going. The more rest you can get the better. However if it’s any consolation, a lot of people start to find it easier before 20 weeks, and the medication helps. For instance I’m still feeling feeble (!), but I can do so much more than I could at 10 weeks (I’m 16 weeks tomorrow). A lot of people find weeks 9-12/13 particularly bad, and then that it gets comparatively easier. But as above, it’s easier in terms of just living with it, not necessarily back to 100% like you were before but certainly feeling much better with it all and having more good days where you can actually do something (I’ve had two days this week where I went out for a couple of hours, last month I was pleased if I managed a couple of hours sitting upright!
To conclude my ramble - drinks. I know what you mean. I went through quite a few things, sometimes they worked for a bit and then I stopped tolerating them but main thing was I was drinking something. For me, my repertoire has included weak peach squash, hot blackcurrant squash, strawberry fruit tea, sparkling water, fizzy drinks (especially Coke/Dr Pepper), and ice cold water. Right now I’m between sparkling water and Coke/Dr Pepper, with the occasional strawberry tea.