Morning sickness tips? Zofran not working

Laura
I finally caved - still getting sick and all day nausea at 25.5 weeks... I am constantly popping blood vessels I my face and the last straw was when it happened in my eye...
The doctor prescribed zofran which I'd Been afraid to take... And it isn't even helping... 
They did some blood tests to check for other causes of consistent nausea and frequent vomiting  but everything came back ok... 
I only feel better if I eat simple carbs but I know this isn't healthy... I'm at my wits end..