My DS is 4 1/2 mnths old he has had a cold the ...

My DS is 4 1/2 mnths old he has had a cold the last 4 days and he has slowed down on his feeding he has only be drinking every 4 hrs instead of every 2-3hrs and he is only drinking between 100-120mls and he has also been sleeping a good 5-6hrs a day where as before he got his cold he was lucky to sleep 1-2hrs a day....I know babies change when they are sick but I am wondering if this is because he was sick or because he is having a growth spirt or because he is just gotten that little bit older and reached the stage where he needs less bottles a day with more volume. If anyone can let me know what there 4 1/2 mnth old is doing with there feeds that would be great. Thanks