What does it mean when a guy blatantly ignores you?

[.]

That's really weird. I can see why you're confused.
So I really don't want to hurt your feelings. You seem like a nice girl. But I think he was just being friendly and being helpful. I didn't see any signs that he likes you in this story. And maybe after, he just thought it was too much? That he was intimidated by you? Because he seems like the nervous type.
And I guess he thought you were stalking him (I don't know something like that or that you were texting too much) and maybe he's just being immature. Like you said. And about school, maybe he has a girlfriend or someone he's interested in and he thinks that you still like him?
I'm just listing all possibilities that come in my mind. Just when you see him, think about what you're going to say and be like "Hey did I do something wrong? You're not talking to me as much as we used to" and just kind of frown at that." Don't text him. Try to get him in person. Or try and call/text him and ask him to meet somewhere with you to talk about things. And be like "I'm sorry if I did anything wrong."