no bowel movement in 4 days!

Ro
My son is 3 months old and hasn't pooped in 4 almost 5 days is this normal? He is exclusively breastfed. Most he's gone is 1-2 days and typically will have a very small amount from his farts. But he's had nothing in 4 days. I'm staring to get worried. I'm going to call his doctor later today.