Hi,
I know the feeling. Same thing happened to me at the place where I said my boss starting smoking again when I quit. Had worked there for over 3 years, even overtime on MANY nights (without payment, mind you) to get everything in order. So, when I became the head of the department, they still considered me as a freakin..... junior!!! They made all these promises beforehand that they would get more people in to assist, because at the time I was doing more than 2 peoples' share of work. Nothing ever came of it, not because there weren't qualified people, but because they did not even try to get me help.
So when that happens, the directors, bosses, whoever, should not be surprised if you want to leave. Companies don't realise that their biggest asset is their people, because if the people are gone, then the company is gone.
The Question is the Answer, and the Answer is the Question!