My dd is the same way, she's 8.
She will get so backed up that when she finally does go she will bleed.

So ped put her on lansoyl, you can get it here in Canada, not sure about the U.S. It's like a jelly and she loves the taste.

Her poops are huge, i'm surprised she doesn't tear.
I'm getting so more for her since ped wants to up her dosage.

I hope this helps.