John and I met in a christian group in university. After he graduated and left for home, we remained closely in touch via Facebook and skype on a daily basis. But we were just friends and I did not have any romantic feelings for him... in fact, he has a crush on my friend.
When he visited over the winter break, things started to happen. My friend rejected him. And he started showing feelings towards me and I just went with the flow. To put into perspective, we were emotionally connected but not physically... and I’m pleased it appeared as such, at least for now. Mutual friends started to tease us after he left for home. I outrightly denied having any feelings for him (not sure if they told him). John and I remained in touch... but he suddenly pulled away one day after I casually asked him about a girl (it was meant to be a joke!). For the past one month, he has been reluctant to talk to me. But when he did, he sounds fine. I tried to apologise and asked if I annoyed him... he denied so. But still refused to communicate. He has been talking to all other mutual friends but not to me. It hurts really badly.
He’s coming over next month and invited me and some mutual friends to a trip. I’m not sure if I should go and how should I react.

Hmm. It sounds like he may have found out about your flat denial of any feelings for him. Or, he has meet someone and is feeling conflicted about his relationship with you. The more important thing to consider is your own feelings. Are you attracted to him? Do you think of him romantically? Or are you just comfortable with him? That will be important in deciding how to react to him. I definitely wouldn't avoid him. Go on the trip. Just decide for sure where you stand first. If you have feelings for him, and it turns out he doesn't have a lady, then talk to him about your feelings. You never know. If you determine you don't have feelings for him in that way, go on the trip. It may help ease things over between you. He may just need time to accept it and move on. You won't salvage the friendship by avoiding him, either way.