help with this

i took my 1 week old to the doctor for white stuff on her tounge this doc i been takeing my 3 yr old to since she was born and we got pretty much told to take her to the hospital she hasnt gained any weight at all since she was born and she has thrush im wondering what i can do for her weight other than taking her to the er and what i can do for thrush im thinking of switching her doc to my almost 2 yr old doc idk why she was so rude to me she been my oldest doc for 3 yrs now.