@SamH & Kev.
Let me just get one thing clear, no, you are correct, I have NEVER smoked tobacco, but this DOES NOT mean I have no clue about addiction or chemical dependency, been there, got the T-Shirt.
So yes, I DO know what you are going through, sure, it isn't easy, but believe me once you have got the habit kicked and realise that the "pain" you are going through now is nothing really that bad, you will come out the otherside a better person, and very probably be as smug about addiction as I am.
But please, PLEASE don't tar me with the typical non-smoker, doesn't know what he is talking about brush, because that just isn't me.
Sorry if I made you feel bad earlier Kev, IMO, making light of the situation and keeping a sense of humour is one of the key aids.