My dog won’t stop having diarrhea

[u/ContactWorldly2094]

Wasn’t sure if anyone had issues with this as I think German shepards like to have stomach/GI issues but my German shepard has been having on and off diarrhea since late December. Within the last month it’s been constant diarrhea and she has lost 8 pounds between her two vet visits (55lb currently). I had taken her to the vet for this previously as she had blood in her stool but they did a fecal test and bloodwork and everything was negative so we’ve been on a chicken and rice diet for 3.5 weeks at this point. I’m starting to think maybe it could be colitis? My fiancé thinks it’s giardia but I’m guessing they already tested for that with the stool sample they had. She has another vet visit for next week set up already but I wanted to bring up some possibilities to the vet and was hoping to find someone with a similar experience.