I had a very similar experience, have posted it here. Short time later I was (and still am) unsure if I wasn’t sleepwalking. But as far as I’ve read about sleepwalking, this seems impossible.
But it felt really unbelievable real. I never had such a dream before. Though I had dreams where I knew I was dreaming (but quickly woke up then), but they were not so real. This was totally different from anything else that I’ve experienced before. I did not try any LD technique, all happened at the typical time for REM sleep. But I had the intense feeling that I should visit the toilet (which was quite true). Maybe your feeling of somnolence was also the very physic feeling of your tiredness?