Dont know if anyone else has tried this but during my first couple of quit attempts I had lots of problems getting a good night sleep for a period of about 1 to 2 weeks after quitting which led to me being in an even worse mood, colds, etc. which doesnt really help the motivation.
Anyway, about 2 or so quits ago (this one will be my last honest :)) I thought I'd speak to the pharmacist about it and he suggested I try something like Nytol and for me it works a treat, I only take half a tablet a night during the first couple of weeks and have no problems getting/staying a sleep at all.
On top of that I find reading a good novel before bed really helps relax me too.. oh and getting some exercise during the day (ideally a jog/bike ride or a good long walk)
Just thought I'd share that in case anyone is having some sleeping issues at the moment!
on that note I'm off to take the dog out for a quick jog!