Why do I feel this way, please help......?

I am deeply sorry, it is always tragic when someone, who has their whole lives ahead of them, is lost. Your daughter may sense your emotion tied to this, and probably feels she can only open up to someone else because she know's how hurt you are also. I suggest the two of you set aside lunch dates, and movie dates, and keep postive conversation open. In times like this the world really can show you it's darker side and you need each other to help heal. In the mean time perhaps talking to a professional would bennefit you as well. You clearly are going through a dark time, from pain felt for your daughter. I wish you the best.