HELP!!! Baby is constipated...

My 5 1/2 month old has been struggling with his poops for 3 weeks or so. We took him to the doctor but like ALWAYS he said it's normal and nothing to worry about unless he stops eating from being too backed up. My poor baby struggles so much to get any poop out that he cries when he is trying to push and wakes up crying sometimes as well.

He used to poop after every feeding and now he's lucky if he gets 1-2 good size poops every 3-4 days or so.

Also, today he hasn't been eating as much as he normally does and he has been VERY fuzzy. He did however get a good size poop out today.

I also think he's teething because he has been drooling like crazy for about a month or two and he chews on EVERYTHING.

I have been giving him prune juice and apple juice in small quantities because they seem to help with the constipation a little bit.

I feel so bad for my little guy and I just want him to feel better. :(

Any advice or suggestions would be greatly appreciated.

Thank you.