Is my boyfriend trying to run away? Or is he just giving me space?

So to make a long story short, me and this guy have been dating now for about 5 months. He is the sweetest most thoughtful guy I’ve ever met, and only treats me like a princess. I have so much trust in him, for everyone knows him as a genuine and trustworthy guy as well. As I planned to go on a 2 week vacation to Europe, we saw each other every day leading up to my departure and it was very hard to leave each other. He was extremely sad to see me leave and could not stop expressing how much he will miss me. He even wrote me a letter with all the things he appreciates about me hidden in some clothes he returned before I left. He kept asking that I text him and FaceTime him while I’m away and was overjoyed to see photos and talk to me while I am away.

NOW.... he hasn’t initiated talking once my entire trip. We hardly text and when we do, I am the one to text first and he takes hours to reply and uses many short cuts. He does not seek enthused to talk to me or check up on me at all. I even say I miss him and he did not acknowledge it at first. This may sound creepy or stalker ish, but some of us instagram ladies have to admit they have done this before. Its not like he is “just busy” because I see from Snapchat and Instagram updates that he is online and using his phone. But not caring to reply or acknowledge me I suppose. I want to think that I’m overreacting but I am very confused. He is not reciprocating any of the affectionate texts I send. My gut feeling says something is wrong. But this is so unlike him I do not know what to think. I could make myself feel better by making a million excuses for him trusting that it’s situational. But I feel like a fool doing that.

What do you think?