What is age of baby. How about, feeding, activity, weight gain, vomiting. What's colour of urine. Well it's normal to pass urine after every feed for a baby less than 6 months. If all above is fine not to worry. Just make sure you are making the formula in a right dilution and feeding her every 2 hourly and again I will advise you to give breast milk rather than formula if possible. Take care.