Tamiflu help

Hi guys. My little one is 3 months old and my brother who lives in the house with us has been diagnosed with the flu. We quarantined him to his room as soon as we found out and started disinfecting immediately. It’s been 4 days and she has no signs or symptoms and seems healthy. My provider started me and my husband on tamiflu preventatively and I called her pediatrician to get recommendations and they originally said practice good hygiene and keep them far away from each other. Then this morning I got another call from them saying the doctors at the practice all agreed that she should be put on preventative tamiflu... I normally 100% listen to her doctors but she seems good and tamiflu has give me and my husband some gross side effects (headache and diarrhea). So I’m really really really confused on what to do. If I don’t give it to her and she gets the flu I will hate myself. If I give it to her and she has side effects I will feel awful. Any advice???

Update: My husband and mom agree we should get it to keep around and the moment she starts acting sick or different we will give it to her.