Thank you for your query,
Bactrim is given as a antibiotic prophylaxis
in children with urinary tract
infections with underlying vesicoureteral reflux
Continue the medication as advised by your Peidatrician.
Appetite will slightly decrease at the end of 1 st year and if the child is active, gaining weight nothing to worry.
If the stool is chalky yellow and the urine is dark yellow, then it may be due to jaundice, but only stool is chalky yellow it may not be a problem.
Consult your Pediatrician
for examination and to assess her weight gain.
Hope I have answered your query.