I fell asleep quickly when I got to bed last night but then the phone rang and woke me up twice. Then I had trouble going back to sleep for the second time. After I had been lying down and trying to go to sleep for perhaps one or one and a half hour, I entered some strange state. I was awake and had my eyes closed and it felt as if I was falling down into my bed. After a while the direction changed and I fell “upwards” instead. I know this stopped and recurred about two times and I had pretty much control over it. I also remember that all times it felt like my heart beat and breathing stopped for a while, and perhaps they actually did. I felt as if I had to force them to get back to work again, otherwise I would die, and I did. This makes me wonder how much of an nd this was. What kind of experience do you think I had?
I think you were close to a WILD, since the things you described fit into SP and HI-territory’s…
And a lot of people have a feeling of dieing during SP; e.g. they start to think they don’t breathe anymore.
Some people say that this is a sign of a trance or an Out of body experience.
Needless to say, you are rather lucky: people spend months trying to get that far, and you achieve it in one night, by accident…
Guh.
Congrats anyway.
Zewu, be happy. If you can achieve this state easilly, than you’ll do great with WILD. That’s just an SP, the first time I had it was exactly as yours(tough it wasn’t the phone that woke me up lol). You can get scared the first time, but then it’s just fun, and can lead you to many LD’s. 
Nicely done (even if it was accidental) 
Yeah, WILDing is definitly a unique experience and everyone’s is different so it’s hard to say exactly what you felt. But I know what you mean when you feel like your heart/breathing stopped, its usually when you’ve entered a dream state. Its nothing to be concerned with though, just think of it as drifting through outer space in absolute silence.