N.B.
I breast feed my child as well and when he started going through this I had to do a little more. Being a young mother(age 20), I talked to my grandmother and what I had to do is add cereal to my breast milk. Breast milk is very thin, I would add about one teaspoon or tablespoon to the milk depending on the ounces I gave him and it would feel him up for awhile. You are not doing anything wrong, he will soon come out of it. Most likely he is hungry, he is going to he needs a little more to feel him up. Hope I help, good luck.