I have feelings for a friend I'll never see again. What should I do?
Have you tried moving on?
Yes, I can't help it. I'm in love with him.
It can be difficult to let go of someone you cared about who's gone.  But holding on to the past is unhealthy.  You need to move on!
What if I can't and I don't want to forget him.
It will only cause you more pain. You will have to find out some way to get over it. Finding someone new might help out a lot.