Jeremi,
I know the feeling it has happened to me also. I have found that you need to keep the same speed throughout the retrieve once the fish is following the streamer. I saw the fish chase it and I was so into watching that I forgot to keep stripping and the fish took off. SO much fun to watch these monsters come up from the depths to take your fly, and so hard for me to relax and keep cool. I seem to get too excited!!!!!