That sounds like a truly horrible experience. I hope it doesn't make it more difficult for you to trust going to sleep tonight.
Have you have a nightmare like this before? My grand daughter (and my son many years ago) suffers from night terrors, even now at 21. What you experienced sounds similar. Night terrors happen during deep non-REM sleep. Unlike nightmares (which occur during REM sleep) it is not technically a dream, but more like a sudden reaction of fear that happens during the transition from one sleep phase to another. Shawna says that at times it actually feels like someone is sitting on her chest and won't let her up, and sometimes she feels like she is floating in the air but it is always accompanied by a sense of danger and fear. It can be extremely scary. She has trained herself to realize even when it is happening that it's not real. I hope you don't have any more of them. Please view Gary's involvement as being only because he was on your mind at the same time. Losing him is bad enough without having to be afraid of dreaming about him. (For further reference http://www.nightterrors.org/)