Need advice- boss asking for a doctors note

Alright, I'm needing some MAJOR advice- there's a little backstory to it though. I'm currently 24 weeks pregnant and have had a really bad uti for about two weeks now, the prescription that my doctor has prescribed hasn't helped yet. This weekend I had a fever off and on, cramping really bad, nauseous, all that fun stuff that comes with a UTI. I live and work in FL and boss had a educational trip planned in TX tomorrow through Saturday. I don't feel comfortable going for a few reasons:

-there's a hurricane coming, that's supposed to hit Saturday, which could cause us to have to be in TX for longer than planned

-UTI's can cause preterm labor (what happens if I go into labor when I'm out of state)

-holding your urine when you have a UTI is no bueno

So today I called my doctor requesting a new prescription and a note saying I could basically get out of traveling. I had to talk to the nurse, and when the nurse called back she gave me my prescription information and was about to hang up. I asked about the doctors note and she said "oh... uh.... yeah, it's fine to travel." It sounded like she forgot and didn't ask the doctor.

I told my boss today I didn't feel comfortable traveling because of the UTI and she's pretty upset- saying she "may" need a doctors note, but not for herself, for the hotel to get a reimbursement. Does anyone know if this sounds right? And how do I get a doctors note if the nurse won't even ask the doctor..