Day six started with me being tired, so very tired that I took short half an hour nap only couple of hours after waking up. I don't think I slept very many minutes, but anyway it helped me to got through the day. I took my 1,5h nap a little later and I'm once again a bit tired but at least I was having REM.
This relative drowsiness every time I wake up should be subsiding.. I at least expect to feel more rested once my body is fully adjusted.