When I got my 1st ecig on 110709 I chain vaped from the time I opened the package and got the batteries charged. All I had was 16mg nic juice and it wasn't satisfying me.
So I bought higher levels, 24mg and have pretty much stuck to that but almost ran out completely last Friday, so mixed vanilla 24mg with 16mg filling a bottle and vaped away all of Friday and into Friday night on that.
I woke up Saturday and felt like I was drugged - no, not hungover!

Light-headed, woozy, ditzy, dopey is how I'd describe it.
I figured out I must be having nicotine withdrawals, so like a good addict, made myself get up and took my hub's 24mg Kamel nic juice and vaped away on it for a while as the dizzy light-headed woozy feeling started to dissipate!
I have stuck to 24mg nic juice and have been back to "normal" since!
So there's an experience of nicotine withdrawals for anyone interested or wondering why they've gone brain dead for no apparent reason!