sitting on edge

I posted a comment on my sons face book thanking him for serving our country and if his father was alive he would have been so proud of him. It was the first time he commented on my post. It was a simple "thank you mom." I've been hanging on the edge for so long waiting to get a responce from him on face book. It's amazing ..as much as I try to convince myself that I can live without constant contact with my children, I still long to hear from them each day and am overwhelmed with gratitude when I do get some sort of communication. So, why than am I feeling so miserable? I don't understand me!