Anyone else give 6 week old baby prune juice?

Ocean

My pediatrician said I can give her a ounce of prune juice mixed with a ounce of pedialyte once a day inbetween feedings for constipation so I did that today at 4pm since she hasnt pooped in 5 days and she had a major poop blowout but she is still acting like she is in pain and its almost impossible to soothe her im getting worried anyone else been in this situation what did u do? I'm starting to feel bad for giving it to her