Ondansetron (Zofran) stopped working ...

Anyone else experienced that? What did you do? I am at the edge of desperation 😢 I am 12w6d and suffered of HG since week 5.. tried the usual suspects (cyclizine, prochloperazine, metochloperamide) none of which worked and ended up in hospital 2 weeks ago on IV fluids.. they prescribed Ondansetron, which seemed to do the trick up until a couple of days ago and then the sickness started again... I truly feel down, so any good tip or positive story would really help 😔