Yep - definitely a lucid dream. But like you said, for only a second
You need to try keep calm, and if you wake up, go back to sleep and try again. Its much easier after that

Also.. if the dream is changing (but you arent waking up)... then its a good idea to keep saying to yourself 'Im dreaming, Im dreaming'
Keeps you thinking of it - in the next dream you should still have it on your mind