My 12 year old daughter was diagnosed with flu on March 6. Took Tamiflu . She started feeling better. Then she crashed again with a secondary infection on Monday March 10.. Sinus infection. She is 875ml of Augmentin since Monday. Today, no fever, all blood work came back normal, still has a cough , BUT she is VERY weak, achy and feels like walking down the hall is a marathon. Should it take this long to feel better? I m worried. Could the antibiotic make her feel this way? Please advise. Thank you!!