my baby has been having yellowish green poop (looks a bit sticky too). it's less grainy and much more watery. should I be concerned? she's 4-month old, fully breastfed.

Is this a one off occurrence or has this been happening often? If you notice a succession of watery green poop, your baby may be consuming more foremilk than hindmilk. If baby drinks more hindmilk which has a higher caloric count, your baby's poop will be more yellow than green. http://www.babycenter.com/404_whats-the-normal-color-of-a-breastfed-babys-bowel-movement_8830.bc

Breastfed baby poop is consider normal when it's a mustard yellow, green or brown color. It is typically seedy and pasty in texture and may be runny enough to resemble diarrhea. You may want to refer to the link for the color chart :) https://www.unitypoint.org/blankchildrens/article.aspx?id=40567710-74c7-4ef2-a040-847be9fbd35a

You may wish to refer to this picture