My LB is coming up to 12 weeks old and is EBF. I've noticed his nappies have a strong urine smell to them during the night. He has been eating well 10 feeds yesterday average time of 27 minutes per feed... the nappies feel heavy enough and no other apparent symptoms. He has been sucking his fists a lot and drools a bit too... any ideas if this is normal enough and what causes it?