Trying to figure out the answer to: I cannot say clearly how I entered there, so drowsy with sleep had I grown at that hour when I first wandered off the true way.

I'm sorry, what type of answer are you looking for?

From the text, we can infer that speaker might be dreaming, but more plausibly, the speaker is atttempting to recall the moment at which he made a poor decision..... took the wrong path.