That sounds a lot like the stages right before a "Wake Induced Lucid Dream" begins. There are three possibilities which arise from this state.

1. The person becomes scared by the strange noises, feelings of fast movement, etc., and wakes up.

2. The person forgets their intention to have a lucid dream, and ends up entering a dream oblivious to the fact that they are indeed dreaming.

3. The person remembers their intention to have a lucid dream, and successfully enters the dream with awareness.

It sounds like you fit in to group two, but it is good that you had this experience , because next time this happens you will know not to be afraid, and to remember your intention. Good Luck!