My new born baby boy is 2.5 month old. He is completely on feed. One query?

Nowadays he feeds on only for 5 to 10 minutes. Earlier he was feeding for 20 to 30 minutes.He was urinating 17 to 18 times in a day but now he does only 10 times a day ( in 24 hours). He was 3 kg (6.6 pounds) when born, he developed jaundice in first week and his weight reduced to 2.4 kg (5.28 pound), he had difficulty in latching hence did not feed that well for a month, but after a month he latched on properly and since then has been steadily gaining weight.5 days we went to doctor and he weighed the baby and he was 3.88 kg (8.5 pounds). My questions is why is my baby spending so less time on i.e 5 to 10 mins. Why has his urinating frequency reduced? We as parents really concerned. Baby remains active when he is awake and sleeps through night, We are very concerned.Please help