Try to reassure your daughter that you have confidence in her as a "big girl" and that you know she can take care of herself. Let her know that you will always make sure she is safe. You may want to cut back on your trips away from home for awhile and let her gradually get used to being away for longer periods of time. Try to be patient with her as she goes through this time.
If your daughter's fears continue, talk with the school counselor. He may be able to give her some individual time or include her in a small group. If you decide that your daughter needs additional help outside school, the counselor or your pediatrician can refer you to a therapist in your community.