Should I call my boyfriend to make sure he's ok?

I was texting my boyfriend earlier and he was a little upset about something, but said he'd tell me when he saw me later, since we were planning to hang out tonight. He said it wasn't me, and while it's still a possibility, everything seemed fine earlier and I haven't done anything. So I don't think it's me. I haven't heard from him since 5. He always texts me back. This is unusual and I'm worried about him. I text him asking if we were still hanging out tonight, and then again asking if he was alright, and then one more time just saying "hello?" I'm genuinely worried about him. Would it be to overbearing to call? This isn't like him at all. I'm worried something is wrong.