It has been said by many a great thinker that pessimism leads to nihilism. In fact Nietzsche even said this, and he saw nihilism as something of a disease. Though it may be true that pessimism can lead to nihilism, I would suggest that it need not be the case. Personally, although I express a level of pessimism towards humanity in general that is probably well above average, my pessimism within the scope of my own life is low. Perhaps this is internally inconsistent, or perhaps it means subconsciously I am setting myself apart from the rest of humanity.
I hope that it is neither of those things, but regardless, my path to nihilism was not an emotional one at all. It did not arise out of a sense of despair at a lack of meaning, as I had already rejected inherent meaning in life or the universe many years prior to realising that this was, in fact nihilism. Even then, when I first came to the conclusion that a lack of meaning logically followed from a non-teleological view of the world I experienced no existential crisis. Self-created meaning just flowed naturally and intuitively to me.