Left without an explanation

I recently met a guy online and everything was fantastic, proper conversations, loads in common. He was really excited to meet me and kept pushing for us to spend some time together. When we finally did meet up, watching tv, with my friends in the house, having great talks, all getting along, things seemed great. He left to run home for a minute and said he'd come back and get us some drinks. Was all smiley and everything. He didn't come back, hasn't rang or messaged me, he only lives down the road. Thought everything was going well but now I'm not sure. I've texted him once and gotten no reply and I have no intention of being a pushy person and asking for an explanation but I feel I deserve one. What's the best thing to do?

Have you backtracked everything that happened that day? Sounds like something spooked him.

I have...nothing happened : It makes no real sense. We met up, we hung out, he left abruptly, but he was chatting away and smiling and said he'd be right back.