HELP ME. my son has been totally dif the past few days. doesn’t smile. doesn’t play. doesn’t laugh.…

HELP ME. my son has been totally dif the past few days. doesn’t smile. doesn’t play. doesn’t laugh. ( he always laughs ) he even whines in his sleep. literally. idk what to do. he’s going to the doctor today to see if maybe he’s sick. but it’s breaking my heart that i can’t even get my own baby to smile. i’ve tried everything to soothe him. nothing works. the only time he’s not crying is when he’s eating or sleeping. thoughts please!!!!!!