Sleeping and eating

[Nicalo2019]

Hi all, my LO is 11 week old on Wednesday, he's always been a good eater. He was combined feeding up to 7 week old now he his on formula full time. He was taking 7oz every 4-5 hours however last couple of days he has not been feeding as much, he is having over 20oz in a day but after he has eaten so well n to go to leaving 3 or 4oz each feed seems a bit strange. He has had a bit of a cold the last few days could it be he is a little under the weather.

Thanks