enough feeding or not

Hi my son is 5months & 7 days old. He consumes only 90ml formula milk 3times a day & 1 spoon of baby porridge. He wets around 4 diper a day Dat too not very heavy. He do latch for about 5 minutes for my breastmilk as my breastmilk supply is very less. M very concern if he is getting enough or not. Please help.