Zofran isn't working

This is my 4th baby and 4th pregnancy with hyperemesis. I've taken Zofran with all 3 prior pregnancies and it was a life saver but this time it isn't doing anything at all. It makes me feel drugged and exhausted when I take it and I still have debilitating nausea and if I try to do anything other than lay still on the couch I'm projectile vomiting or dry heaving violently since I can't keep much of anything down. Has anyone else experienced Zofran not helping? Idk what to do, im 8 weeks tomorrow and I can't be useless on the couch for the next 31 weeks until my c section, I have 3 kids who need me to care for them 😭