My son is 6 weeks old and is about 75% breastfed and 25% formula fed. He’s always done well with this combo up until this week. For the past few days he has been throwing up (not spit up, he is violently throwing up his entire chunky stomach contents) every time he has breastmilk, almost immediately after. He’s fine with the formula, no bad reaction at all. He has no change in his poops.

I’m not doing anything different from before, no new medication or diet or habits, and up until this week he was doing fine with my breastmilk. Can anyone help explain what’s going on? Did this ever happen to anyone else? (I am of course going to call his pediatrician about this as well, just looking for some experienced mommy insight)