Last night I was unable to get to sleep. I went to bed around 12am and I was unable to sleep until around 5:30 am. Immediately after falling asleep I have 2 long vivid lucid dreams. This confused me because I have always been told that we don't enter REM until 90 minutes into sleep.

Does anyone know what caused this?

(Note: I woke up after the lucid dreams at about 6:20)