I think accidents occasionally occur when kids are growing very fast. Since she trained, about a year ago, there are times when our DD unexpectedly has several accidents over a few days, and then she adjusts and goes back to her normal potty trained behavior. I actually wonder if the sensations that warn her that she really needs to go are changing, or her muscles are not catching up perfectly with more capacity in her bladder or something like that because it matches up so closely every time. She'll start sleeping constantly, eating like a horse, and being ever so slightly short tempered (yeah, right, just a tiny bit...) and often those times she'll also have an accident, or, usually now she just will leak a tiny amount and then stop herself before she has a full accident and ask to go to the potty.
Especially if it's upsetting him, I think the only thing you need to do is clean up and reassure him just like you've been doing and he'll be fine. I think its a normal process of 3 steps forward,1 step back, yk?
Miss Chris and the guy in the city that never sleeps.
Making a home for our big girl 3/06 and our new boy 2/10