No, its an acceptance that we dont know everything yet. I am surprised by your comment, as you claim to be a pantheist, which is not that far from deism. Hence I propose using a certain set of definitions, that you are an agnostic too.
Let me clarify it again: when I speak of God, I almost always imply a creator God as that is the most widely accepted definition. You are right that we do not know everything; in fact we know almost nothing compared to the knowledge still waiting to be discovered. But I deny a creator God, I do so because the existence of such a God is not logical.
I have completely abandoned any faith in Islam because I realise its manmade. However that does not mean I have abandoned all concepts related to a first cause, just because it is often seen as the antithisis to theism or as a knee-jerk reaction to faith, which is what I feel some may be doing. Before you contest this post, please be aware I dont accept the revised defintion of atheism vis-a-vis Dawkins.
I did not allude to any Islamic belief when I talked of the hangover. The belief in a creator God transcends any particular religion. I prefer to start from a position of zero belief (at least theoretically or consciously).
Unless the law of conservation of energy is proven to be wrong, I find it difficult to entertain the idea of a first cause.