It has been 5 days my 2.5 months old baby has not been urinating since morning to evening( 11-12 hrs) and then in the evening , within 3 hrs he urinates 7-8 times then again whole night is hardly urinates once. Weather is hot here amd baby drinks around 100 ml milk 7-8 times in a day. It this normal for baby to go without urinating for 12 hrs and then urinate so frequently within 2-3 hrs? He remains active when awake.