Constipated baby

My almost 6 month old is constipated. We had issues with her not pooping regularly so I took her to the dr after 8 days of no poop. So we started giving her prunes and other high fiber foods along with apple juice and water to help her go. It helped but now she's pooping every 3-4 days but it's always small hard balls. It seems like the high fiber foods aren't helping anymore. She has an appt next week but I'm wondering what I can do to help her go in the mean time. She doesn't like juice or water and I've been doing warm baths and bicycle legs in addition to high fiber foods