EBF 11 week old with vinegary/yogurty poo

kknoll59

My 11 week old starting having terrible awful gas about 3 weeks ago that smells like a truckers. He has also started pooping less but when he does, it has the consistency of yogurt and smells to the high heavens...I can only liken it to vinegar or something acidy. He doesn't seem to be in any pain, other than normal gassy behavior but just stinks sooo bad and the poop just doesn't look normal. Anyone else seen this??