What does it mean if your stool is green? is there any make concerns or anything to be worried about?

No: No worries unless you have fever or abdominal pain or bleeding.

Bile: The greenish color in stool is the breakdown product of the bile when it has not been in the gut long enough to go through a change to yellowish or brown. It is normal as is the loose consistency. Some digested material will take on a darker tint than others ; the germs in the gut will also impact the final product. I'd ignore the whole issue.