I Need Advice

I recently went to a 3 day camping music festival with a friend who lives out of town. We were having a great time in the first day, hanging out all day together, catching great music, etc. Then the second day we were hanging out at our campsite and he told me he wanted to go find a friend of his that was camped at another site. I said, “Ok I’ll go with you”, since nobody else in our group was currently at our site and I didn’t want to just sit around by myself. So we’re both walking for about 2 minutes when he stops and says, “I’m actually gonna just walk around by myself, so I’ll catch you later.” And then he took off. I was a little caught off guard by this and didn’t know how to react, so I kept on walking by myself. I attempted to find my other friends who were there to see what they were up to but after an hour of looking I wasn’t able to find them so I turned around and went back to our campsite. When I returned my friend was sitting at the camp with his friend that he originally said he was going to look for and he said l, “Oh there you are. Where’d you go?” and then asked me if I wanted a beer, as if nothing happened. I declined and just walked away to make a second attempt at finding my other friends because I felt sort of awkward being around him after he more or less told me to go away. Since then things have returned to normal, we’re actually messaging each other back and forth every day planning another trip together in the fall. I just can’t get that moment out of my head though. Why did he tell me he wanted to go walk by himself and then walk away from me with no explanation like that? It made me feel like he was sick of me and didn’t want me around. It’s bothering me enough that I’m having second thoughts about going on this upcoming trip we’re planning. What should I do? Should I go as planned and forget that small moment? Should I ask him about it? Should I cancel our future plans if this is bothering me? I’m open to any advice here. Thanks.