Aww bless you! I feel your pain-teacher, struggling through ms and nausea with an almost 5 year old has felt like hell at times!
Luckily,Im either more used to the sickness now or its eased up for me slightly, but have a cry when you need to have a cry (it made me feel better), accept that housework u fortunately has to come second and try and get that rest in when you can-Ive found during half term that lying down and watching a film with my DS has really helped, and when Im back at school Im so busy that I dont notice the sickness as much...you just need to make sure that youre looking after you,listening to when your body is saying enough, and let your partner help you as much as possible with the caring of LO and housework and such xx hope it eases for you quickly!