My baby is extra sleepy in the heatwave. He's still feeding, weeing and pooing as normal, only he is needing to be woken up for a feed sometimes and once he's awake he won't open his eyes but is awake to drink milk but not burp properly. It's like he just wants to sleep again. Before he went sleep he was active for about 2 hours where he was wide awake and playing but now during the night he's being the same. He's in just his nappy with fans on. Is this normal??