Ladies.. I can't figure out what's going on.. He sees hos dr Tuesday but I csnt figure out why my…

Ladies..

I can't figure out what's going on.. He sees hos dr Tuesday but I csnt figure out why my son has thrown up.. or a really large amount spit up...

He's bf and formula fed he threw up my breast milk yesterday morning at 7 and he jusy threw up s bit of formula. I've been burping him and he burps good nice and loud what could be wrong?