I have a 4 month old that is constipated. He is BF and has been on rice cereal for 3 weeks because our pediatrician said it would help with his acid reflux. We gave him a glycerin supp. yesterday and it did make him go but he is still straining. I also gave him a little gerber apple/prune juice still not really helping. What do you suggest? He will NOT take a bottle at all not even breast milk. I have to feed him cereal and the prune juice by spoon.