Hi @yellow25 I started taking cyclizine at 6 weeks, I was drowsy for about a week. Not constantly drowsy, but the first day very drowsy, then usually it would be something like napping a fair bit during the day, maybe falling asleep early too, so I definitely slept a lot more but I wasn’t out of it all day every day if that makes sense. After about a week that subsided. I would still get worn out quite easily and sleep a lot, but at that point it wasn’t cyclizine related, just seemed to be me being pregnant and my way of coping with the sickness and nausea! Rest was the best treatment for me. As DeadDoor and Lucinda have said, the earlier the meds the better. Cyclizine is a first line treatment as there is a lot of safety data for its use in pregnancy - the RCOG guidelines provide more detailed info (page 10 gives an overview around safety data, page 25 shows you the treatment options laid out fairly simply by first, second and third line). You can also try the BUMPS website (I can’t access it right now to link because my parental controls are being weird, BT seems to be having an issue!).
I think starting treatment early really helped to avoid things getting worse. FWIW and you may have experienced this last time too, you’re entering the peak period, somewhere around 8-13 weeks (a lot of people especially seem to say around week 9/week 10) is when the sickness and/or nausea can be at its worst. So it would be good to be medicated and resting as best as you can for that period, as it will help a lot, and then after that whilst it’s not necessarily a sudden and wonderful break from sickness (as you already know!), you may very gradually start to get some breaks and ‘good moments’ or even ‘good days’. I’ve been one of the unluckier ones and kept up with sickness and nausea for a while, but I would say it has pretty much eased for me since around 30 weeks pregnant (yay!) as long as I don’t try to do too much, whereas before I could rest and still be nauseous. I’m currently down to 1 cyclizine a day, first thing in the morning (more yay!) and I’m 35 weeks pregnant. But, I stopped vomiting regularly somewhere around maybe 14-16 weeks, it became an occasional thing (the odd day here and there rather than daily or at least several times a week), and seemed to pretty much stop somewhere around 22 weeks I think (bit hazy on the memory but that’s about right). The nausea is what continued more fervently, but as I say that has now largely abated as long as I don’t do too much.
Hopefully you can take it easy over the holidays, maybe a week or so before you’re due back in school it might be worth taking stock and considering whether you’re really ready to return to your usual teaching routine. I know it’s probably a bit hard for the school with the start of the new academic year and there’s quite a few teachers on here who have expressed their guilt at leaving their class and not being able to do much, but, you need to take care of yourself and you won’t be a very good teacher if you’re being sick or struggling to focus because of the nausea. Maybe some of the fellow teachers on here will be able to share some good advice from their experiences. In my experience (not a teacher, I do a corporate role in the public sector) it took me a while to accept I wasn’t going back to work any time soon but in giving myself the space to rest and getting signed off it has enabled me to recuperate and avoid the worst of it, I’m sure it would have been much rougher going if I had been trying to work, commute etc as it was already much rougher when I did simple things like try to stock the fridge!
I hope everyone is doing well, I am practically giddy with joy that it has dropped nearly 20C here - from 37C on Thursday to 19C and heavy rain today 
my neighbours would likely think me mad. Around here some people will complain of the heat, but generally speaking the mindset is, “Great, it’s sunny! Everyone out the house, shorts and vests, get in that sun all day...”, whereas in my opinion this is an extreme weather condition and just as I don’t fancy being out all day in pouring rain or hailstones I equally don’t want to be out in the scorching sun! Our current wetter and cooler weather on the other hand is great, and it means I can actually do a few bits around the house without expiring!