Losing sleep over lucid dreams?

I feel like I might be trying too hard to have a lucid dream... Last night I repeated a mantra for about 30 minutes(yeah it takes a while for me to fall asleep) and Although I didn't lucid dream I woke up after 4 hours of sleeping and couldn't fall back asleep. This isn't the first time I have woken up early like this... What am I doing wrong? And BTW I am not trying to WBTB.

Oh and If you could suggest a good sleeping position to have lucid dreams that would be great. I haven't been able to find one.