I feel for you. Been there and done that as most of us have. I went to England last July and stayed until November. I made it a point to email my closest friends every single day to share with the my experiences in another country and to hear all their stories of their journey back home. I shared photos with them, asked for photos of them and if we did not email every day, we did every week. I made it a point to never let them think for a minute 3000 miles away would get in between our bond. And, thankfully, it did not.
That being said, if you did as I did, and they still are not returning your messages, than you have two options: you can send out a heartfelt email or message expressing your dismay and confusion or you can simply let it go. I suppose this will come down to the strength of your bond with each one of them. My friends, though sad to lose me for 5 months, were so supportive as they had never seen me so happy. Now, that I'm moving in October to live there perm, they are again sad, but comforted to know that while apart before, we never lost touch or that bond. It's all about both sides nurturing and not just one.
Hang in there. When I got back, I was jetlagged to hell, very discombobulated and turned on the wrong side of the road quite frequently that first week or so back in the US. I missed my friends in the UK tons, the scenery and of course my UK BF that is now my husband. You just have to take one day at a time and roll with the punches. Some will knock you down but you have to get back up and stay focused and keep going. Such is life, eh?
Keep your head up!