I suppose your bioclock is suffering a little; been a bit disrupted by your work patterns. I did a stint of 3 months on permanent nights and it messed me up something rotten. Truth is, our bodies are only fit for work while the sun shines, despite what the capitalists try to convince you of. It seems that a lot of people spend their lives half asleep due to damage to their biorhythmns and don't even realise it.

I think it will take time for your body and mind to adjust. You may be experiencing more slow wave sleep due to your change in activities.

What you need to do to increase REM and to counteract the negative effect that this change is having, is you need to learn a new skill a few hours before retiring to bed. be it learning a musical instrument or computer game. The reason for this is because it has been noticed that rem increases when new tasks are learnt...the neurons fire more at night due to it processing this new information that you're feeding it. Don't read before bed though because it will only further increase slow wave!!

Failing that...try a cheese and lettuce sandwich before bed...works wonders for me