Baby girl is not gaining weight-HELP!

January 3 she bit the inside of her cheek and it became infected. She was given amoxicillan. At the end of that ten day treatment, she got a fever, congested nose, cough, and ear infection. The doctor gave her augmentin which I gave her for two days. I then started to treat the ear infection with garlic and mullein oil drops in the ear. She had one mild cold when she was 5 months old. She has had a sick and stessful couple of weeks, but on January 3, at the very beginning of all this, she still only weighed 16 pounds. She is breastfeeding fine, but her solid intake is poor-moderate. I serve her both homemade and prepared/store bought only organic foods. I supplement her diet with probiotics. I startted her on a holistic immune system booster recently. I occasionally give her a multi-vitamin. She has had homeopathic Cold pills, teething tablets, and chamomilla(for teething abd irrability). Thanks, Jennifer