I haven't volunteered in an orphanage before, so I can't give you advice with an EXPERIENCED mind, but I can totally understand what you are saying. In my opinion, it would to completely normal to feel guilty, I understand, you are coming HOME to your family and friends, while they continue to stay in the orphanage. It's sad, but not something you should beat yourself up over.
Your last sentence says it all. Your time spent with them for so long makes it difficult to just leave them. The only thing I can compare it to is an animal shelter, as I've volunteered at one.
I felt so unhappy at night, when I'd come home. All those animals without homes and families, and I have ONE pet...enough room to take them all home from the shelter. The best advice I can offer you is that time heals.
I know, *very* cliche, but honestly, so true. I believe that after some time, you will start to feel your pain and guilt suppress. And who knows, maybe in years to come, you can return to China or Nepal to make new friends, hopefully.
I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.