green stools.. help

In breastfed infant? Ds is almost 2 months old. Got the past two weeks he's had green watery and explosive gas. It got better and started again. I took him to his ped and she said it was probably a small bug out my milk? He's EBF. Yesterday and today he's been fussy which is not like him at all. I have the wonder weeks app it says he's going through a leap. What could this be? Could it be my milk? I know I do have an overactive let down but I think it might be because I had been pumping a lot, trying to make a stash for emergency. Sorry if this is all over the place I need advice??