I'm sorry this has to be the hardest thing for you atm but keep remembering it will eventually pass, also you're technically not sick, its just your mind that's confused cos of all the chemicals..

Is there a reason you need to leave the house? That sounds crazy of me but if you're allowed to stay in most of the time, why don't you plan around what time you usually feel n*... does it kick off before you eat? Or after? I heard not eating is he worst during MS so that could well be your problem....

Are you using anti-emetics? Peppermint gum will ease it quite a fair bit!