You may not want to hear this, but mostly time. You will go through a process of emotions ranging from sadness, hurt, feeling alone, questioning the decision, to anger at different times. Allow yourself to go through them all.
When you are feeling angry, try writing it out in a journal or letter that you burn to let it go. You can also try to spend time with a friend you feel ok to "feel how you are feeling" with, or who you can laugh with, separate from the group during this time. You can also spend time doing things on your own until it passes.
What you are feeling is natural.
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.