3rd night in a row I get lucid, then get excited about it and despite all efforts to remain calm, I wake up within maybe 15 seconds.
In the other hand, I can't calm down and stop concentrating completely - I'm afraid to lose lucidity. (about 2 months ago I had a lucid dream, where I realised it is a dream, but -not quite-, I kept doing the silly thing I was after in the original dream plot and in no time lost lucidity.)

Any advice?