I had sex Tuesday morning and he didn't pull out and that was  3.5 days ago. I'm on the paragard birth control IUD. I got a UTI the next day after sex and I've been taking Cipro as an antibiotic. Today I took Diflucan to prevent a yeast infection. I have been nauseous all day and I randomly though "I could be pregnant". Can you have symptoms of being pregnant 3 days after sex? I also haven't eaten much all day today and I worked out for like an hour. So maybe that's making me nauseous. I'm just freaking out. Please give your opinions.