What does his reaction to "I'll miss you" mean?

When we were saying goodbye before he left for an adventure trip to the mountains, I decided to tell him that I would miss him. I did it shyly, but I approached him and carefully whispered in his ear “you know, I’ll miss you” he smiled and his response was “but I’ll only be gone for a few days” I told him that it didn’t matter, I would miss him anyway. I told him this shortly after he initiated the kisses on the cheeks (and they were really nice, I can still feel them). What should I think about his reaction? We are friends, but I definitely want to be more and I often feel that he feels the same way.

What does his reaction to "I'll miss you" mean?
Post Opinion