What Causes Loss Of Appetite, Difficulty In Bowel Movements And Smelly Poop?

hai sir,
gd eve
my baby was 8 month old. he is refusing food for the past 2 days. he is refusing food by the way of creating some sound ( bur... bur....bur..) and starts crying if we suppose to force. and also he have 2 bowel movements , but it is not loose, thick one and while this bowel movement is face becomes red. and also the baby stool is smelling. give the suggestions sir. i thought it may be due to stomach upset? give the reason and solution sir. thk u.