DW has had hyperemesis three times. We've not encountered anything to either prevent it happening, or relieve it once it strikes. We did try some megadoses of Vitamin B21 before our last pregnancy, and in the end, it was the worst!

Good luck. I think the best thing you can do is plan well ahead to try and have your life and affairs in order so that you have as little responsibility as possible during your sick months. It has certainly been severe enough for us that it has led us to delay the conception of our next bub until our little ones are older and more independent (and in school!) and I can save up some money to take some time off work.