Baby poop

My baby is 13 months old & she has had diarrhea for an entire month. The first 2 weeks she had it, was due to a stomach bug because everyone in the house got it. She's the only one that's had it for weeks. Her poop was starting to get hard so we started her on whole milk mixing 3/4 formula & 1/4 milk. Shortly after, the diarrhea returned and now I'm not sure if it's another bug or because of the milk. I've contacted her doctor and she doesn't seem concerned but my baby has had diarrhea for a MONTH and I'm concerned. It's not so much even poop anymore it's just straight yellow water with a couple of strands of poop. She still has an appetite and is acting like her normal self so I'm not sure what the problem is. Does this still sound like a bug or

should I take her in to emergency since her doctor won't see her?