I'm no expert but I'm having similar issue here with my week old. In my case, it turns out she wasn't getting enough milk from me (not sure if it's a supply issue or just that it has not fully come in yet). We started giving her 15ml of formula through a syringe while breast feeding and now she sleeps independently. If she falls asleep before she has nursed ~10 min on each side, she ends up rooting shortly afterwards/waking early.