I'm sure your SAD is exacerbated by your shift pattern too - as if you have some ever-changing form of jet-lag. Melatonin would prob help - there is also a fabulous product that you can get from the States "Sleep System' by Rainbow Lights. It's a damn sight cheaper than £150 and worth a go. It is basically a vitamin supplement with a small amount of Melatonin in it. I got when travelling back and forth from the States alot. It really works and you feel refreshed on waking not as if you have been hit over the head with a club hammer which helps! You could also do with taking a Vit D and E supplement. Washing it down with Red Bull or Coke is probably best avoided though! Good luck - SAD is really disruptive.