So dinner time at 7pm she only drank 70ml she normally drinks 100ml to 120ml her bottles were all normal apart from the bedtime one. Went to bed at 8pm and i feed her at 4am (she didn't want the full bottle coz she was extremely tired as she didnt nap much that day) so she was down for 8 hrs. I changed her nappy and it was completly dry

If on her next feed its dry im taking her to the hospital but has this happened to anyone befor at what hour should u be concerned at?