My son is 18m and has nearly white mushy poop, he is a very fussy eater and has been ill a lot since the day i gave birth to him. should i be worried

Mushy poop: He may have celia's disease. Have him examined by a pediatric gastroenterologist.

I would: Even though it's late for the presentation (18 mo), acholic (white stool) rises a concern for the biliary atresia (blockage of the bile from the gall bladder to the intestine). If your child also has a dark urine, jaundice (yellow skin color) or icterus (yellow eye sclera). I would evaluate his total & direct bilirubin level with the liver enzymes and get a sonogram of the liver/biliary system.