Zofran prescription?

Wondering if it’s worth calling my OB to see if she’s comfortable calling in a Zofran prescription? I’m 7 weeks with baby #2 and I was stupid enough to think this pregnancy would be different but, my aggressive HG kicked in a week ago and I have not kept down a drop of liquid since. My OB knows my HG issues from my first pregnancy but, I don’t see her for my first appointment for another week and I don’t think it’s healthy for me to keep going like this until then. Is giving my OB a call about possibly calling in a prescription even worth it or will she tell me to wait until she sees me? Literally every other nausea med failed me last time, only Zofran worked so I’m confident hats what I need.