Maybe a dumb question

So I'm 35 weeks and I've had fluid in my ears for the past 3 weeks or so. My ear just started hurting today though So i think I'm actually starting to get a full blown ear infection. I go to my OB in a couple days. So do i bring it up to them or do I call my Primary Dr? My main concern is in 3-1/2 weeks I'll be having my scheduled CSection. So i hate to take an antibiotic in case I'll need one for the csection. Which brings me to my next question. Do they automatically give you an antibiotic as a precautionary for csection?