Welcome to the DV

This thread reminds me of the first lucid dream i had, i had exactly the same problem. over time i learned 2 techniques that help to bring stability to your dreams

Hand rubbing
when u realise u are dreaming you need to rub your hands together feel you hands concentrate on them. this wil help you to bring stability back to your dreams

Spinning
just spin as fast as you can, feel the spinning motion and concentrate on it til your dream is stable again

good luck with lucid dreaming.
i prefer hand rubbing because Spinning makes me loose vision and changes the dream scene