My 5 month old has been pooping after every feeding for nearly a week now and this hasnever happened before should I be worried?

Maybe. Bf infants can stool a little smear every feed or a crib full once a week.Bottle fed kids are expected to go daily.If you have added juices they can often loosen up the process and increase frequency. If the kid feeds and acts great, I would just monitor things.
Probably not. If she's still peeing fine and there is not blood in the stool i would recommend following it. If she cannot eat or pee because of the extra stooling then i would be more concerned. If there is blood mixed in her stool , i would be immediately concerned.