My 3 week old just pooped a hard pebble poop! I did run out of his formula yesterday so he had a few bottles of a different kind, because it was like -40° and I couldn't take him to the store. Could that be why? He usually takes Gerber soothe and I gave him enfamil gentlease. They sounded the same but must not be :( I had no idea 2 bottles would cause a problem. I feel so bad. Should I wait and see if it fixes itself since hes back on his regular formula? I dont think it's worth bugging the dr over the weekend? Idk :( I feel bad. He isnt crying or anything, but hes grunting and pushing. Anyone have a baby with constipation this early?