Ds wetting pants every day

[icelollycraving]

Ds is 5. He suffers with constipation but it's under control most of the time.
Over the last month or two he's been wetting his pants everyday at school, sometimes at home on weekends too. We remind him at home but obviously at school that wouldn't happen.
We have done sticker charts, rewards, I've also got frustrated and said he's a big boy, he shouldn't be having accidents. He wears a pull up at night which is always full.
He's not telling anyone he's had an accident so he's getting sore & a bit stinky. Some of the older kids have told him he stinks which made him sob. He hasn't told the teacher as he said he's worried about getting into trouble.
We aren't telling him off but none of his friends are still not having accidents. When it was once in a blue moon I wasn't at all worried,I figured he'd be dry in time at night.
Now I'm getting frustrated with wet clothes and he can't tell me why he isn't using the loo. At home he rushes, almost as if he leaves it to the last minute.
Has anyone had this? His teacher is quite dismissive to me but he genuinely likes her & the TA. I wondered about taking him to gp but I think he'd freak out a bit & I don't want to make it worse. He is one of the youngest in his year.