M.R.
It depends on your daughter and on the circumstances. If it is a safe overnight, and she is ready to be away from you, send her. Day camp is certainly not something to be overly worried about, your concern for her safety should not keep her from experiencing safe outings, and is there to keep you from sending her places she should not go.
If your worry is out of proportion for what you know to be safe and good for your daughter, then you should be looking at yourself, and go ahead and send your daughter. You seem to be saying that you know you are having unfounded anxiety, not about the experience, but about how you will feel by sending her. If you think that you can get over it yourself, then I would give it a try. If you can't keep from imposing your anxiety on her by holding her back from appropriate experiences, and know that you are keeping her from doing things that she will enjoy, is ready for, and are safe, then you might consider seeking help to deal with the anxiety. A little is fine and healthy, as long as you don't let your fear stop her from having a full life!
I hope it gets better and that you decided to let her go.
M.