I feel 6w baby's joints crack all the time, especially during diaper changes & holding her. sounds like cracking knuckles. is this normal? scared!

Joint "popping" is: not anything to worry about, except if the popping is of the hip joints. Pediatricians routinely check for congenital hip dysplasia with ;dislocation. Grunting & turning red in the face to expel gas or normal stools is because the smooth muscle of the gut does not yet work in a coordinated manner. Learn the "football hold" or "colic carry" for the next few weeks. This,too, shall pass.