breastfeeding poop issues

Ann marie
Ok my breastfeeding baby hasn't pooped in 6 days! I'm like WTF and I called the dr yesterday to see what I can do to help her. She's not in pain or discomfort... pees a lot too!  I was told to give her pedi light ( I thought that was for dehydration when their sick) , told to give her warm bath which I do every other day for her normally, bicycle movement on her legs which I do every morning at tummy time for her, and s suppository as a last resort... gave her the drink but thought why not prune juice??? Isn't prune juice safe for 4 months old??? Any suggestions on helping her stay regular?? This is the first long time she didn't poop she is usually everyday one poop girl or every other.