Of course you're going to have those feelings. But the longer you dwell on them the more they take over.
The trip is a great idea. You'll be doing something good and sharing that experience with new people. At the end you'll have some new friends who are all your own.
I hope you reach the point where you realize that you will be fine no matter what happens.
If you love somebody, set them free. http://tinyurl.com/2empx2g