Faking out my fake sugar addiction

I've been trying to cut down my caffeine and my artificial sweetener use lately. 

To that end I have halved the amount of aspertame (fake Equal) that I put in my coffee (which I'm making weaker). I've also vowed to intersperse water with my diet Cokes or iced tea (which I sweeten with fake Splenda) during the day.

Yesterday went well and I noticed that I slept really well last night.  I suffer from insomnia - waking almost every night between 12:30 and 2 and being unable to go back to sleep until it's time for me to get up at 4:00 - but I didn't wake at ALL last night.

Is it the lowered caffeine?  Or was all the 'sugar substitue' to blame?  Or was it just a fluke?

I'll keep you posted!