12 y/o son and weird digestive issues

[Antares444]

My 12 y/o son started having weird digestive issues a year ago or two. He sometimes has transparent mucus with stool or instead of stool. There are weeks when everything is all right and he can eat whatever he wants, but there are periods of time when he has a lot of gas, needs to poo frequently but in small amounts (he says he can't empty everything at once), and when we travel or he has a test in school he always needs to use the toilet more times.
He was tested at the hospital (blood, stool, lactose intolerance, gluten intolerance, allergies) and all the tests are OK. The specialist told us we can be calmed, that all the tests are negative and that he doesn't need further tests or exploration.
I suffer from health anxiety, unfortunately, so his answer didn't calm me down. Why is my kid having issues if everything is OK? He is an anxious kid who worries a lot about grades, school, etc... but he has great friends and loves being there so I can't help wondering, is this caused by stress? My mom and sister suffer from IBS but my son is too young to have that, isn't he?
I wish somebody could give me answers. What to do when we travel, when we go hiking, when we simply want to spend one day out somewhere, why does he always have issues when we go on a trip? I'm sure there must be a reson, and a medication that might help him...my mom got pills.
Is this one of those puberty issues that might just disappear some day?His pediatrician won't see me anymore, she says he's growing nicely and gaining the right weight and that's the important thing. But again, why these life-limiting issues if he's fine?
I guess I just needed to vent and talk about this to other mums who might have similar experiences.
Any insights here?
Thank you!

Hi, my son is similar and we've just been through all the tests too. He's 11 and gets anxious too which definitely doesn't help. Dr diagnosed IBS.

I suggest doing the low formal diet to see if it helps.

You're transferring your health anxiety onto your son. Please stop.

Thats textbook IBS which flares with stress. You need to see a psychotherapist to deal with your health anxiety ASAP.

My IBS started at age 10 or 11 so he is not too young in my opinion. The mucus sounds like he is constipated and is maybe stuck in a cycle where he is bouncing between looser stools and more constipated stools, especially if he is stuck in an anxiety cycle where he is anxious about going out, so he gets loose stools and so gets even more anxious next time he needs to go out, which then in turns makes him want to go to the loo even more.

Could you do age appropriate relaxation exercises with him, to start to try to address the anxiety and to regulate the bowel maybe flaxseed or psyllium mixed with water. These types of soluble fibre can soften hard stools but also "thicken" (sorry I can't think of the right word at the moment) loose stools depending on where he is in the bouncing back and forth cycle.