It all sounds good, but help me out with a bit more info. Is she back to her birthweight? How often does she poo. Poo ( not so much wee) is the 'gold standard" for understanding if your baby is getting enough milk. So we want to see plenty of poo!
Some mums find that if they give their babe 20 mins on one side, break the suction and take her off, burp and change ( to wake her up a bit) and give her the other side, baby takes more and settles for a (bit) longer! She is sleeping very long periods at night so will need to feed a lot during the day! At 15 days nothing is a habit!
You can never go wrong by offering her another feed- feeding cures most woes for a baby