So Frustrating

Not knowing what to do in a situation can be one of the most frustrating things ever. Especially when the situation has happened before, and you did what your instincts told you to do, and everything was ok. But every situation has variables. No two are the same. Especially when it comes to L.
L is eight years old now. Not a teen, not even a pre-teen really. So when he shuts me out, and refuses to talk to me like a teenager might do to their parents, it DRIVES. ME. CRAZY!
I'm so lost. I don't know what to do. I've never faced this problem before. And yeah, it's such a small problem in relation to other problems other kids have, but this is my dilemma, my blog.
Here's an example:
Yesterday, I picked him and other kids up from school. Outside the school there is a small hill, that's covered in ice. Not a safe situation, but a fun one for any kid not concerned with head injuries. The kids were playing on said hill, blowing off after-school steam. Everyone was fine. L was fine. L was happy.
I gave the "one more turn" warning, and after that, turned and left. Like the Pied Piper, children followed me.
As we approached home, I noticed the gloomy look on L's face. "Now, what?" I thought. I asked him what was wrong, and he ignored me. I tried to stop him walking and look in his eyes, but he wouldn't meet my gaze. I asked again, and again, he shrugged me off and pushed past to continue on home.
And again this morning. We were walking to school, everything was hunky-dory. L stopped to slide on some ice against my advice, and the other kids were still continuing on to school, so I did too. We were only next door to the school, and I left him behind. He was not crying, he wasn't shouting, "Wait!". He didn't seem to care. And he's 8, so he can manage to walk that short distance by himself.
When we arrived at the school, he had caught up, but had that disgruntled look on his face again. I asked what was wrong, and he wouldn't answer. Again.
This kind of thing just makes my blood boil. I can't even begin to describe the inner turmoil I feel, how ANGRY and FRUSTRATED it makes me feel! I want to take him, and shake him. I want to force him to tell me what is wrong, why he is behaving like this. I want to threaten him with punishments if he continues like this.
But I don't.
It takes EVERYTHING, every ounce of control I have to walk away and leave it be. Because there isn't anything I can do. It's out of my hands. It's out of my control.
But it's not right. He shouldn't be shutting me out. Not at his age. He is still young, I feel. Logically, your mother should be the one you turn to for comfort at his age. He should be looking to me to make it better. Why is he bottling up these feelings? Is it to punish me? To make me hurt too? Because that's what it feels like.
And the frustrating thing about it is that I can't see what the sudden mood swing is from. What happened between minutes 35 and 36 of that hour? He wasn't hurt, he wasn't shouted at, he wasn't ridiculed or poked fun of. What was it?
It angers me too, because he is ignoring me, and to ignore someone when they ask you a question is just the height of rudeness in my book. And you don't ignore your parents.
So what do I do? Do I continue to question him, to demand an answer because he should not be getting away with this behaviour? Is it just bad behaviour, another form of manipulation?
Or do I leave him alone, respect his wishes? Do I allow him his privacy to brood? Do I recognize that maybe he can't help this behaviour?
But bottling up your emotions isn't healthy, right? Doesn't that lead to more problems? Shouldn't he be forced to explain what he's feeling?
The dark looks directed at me during these times (and those two examples are MERELY the tip of the iceberg!) scream to me that his ire is focused on me. That I've done something wrong, or that he wants me to notice that he's upset at something. But if the goal is to get me to notice something is wrong, then bloody well tell me what it is!!
So if he has a problem, a real issue with feelings and sorting through them, then I need to help him. But I don't know how.
And if it's a behaviour thing, then the answer to me is obvious; I need to ignore the behaviour and show him that if he wants attention, he can get it by cooperating.