Mothers who breast feed with babies going on 4months

Hi guys so I wanted to know who has a baby who will be going on 4months or already is my son will be 4months on the 18th which is Saturday. Also my question is if anyone can help or give me some great advice this would be truly wonderful and helpful but I had to get off work early yesterday & fun to a interview so my milk is low for today I need to know can I start giving him stage one baby food or what can I do to help him stay full . He only has been having JUST MY breast milk.