Don't stress about it. Dreams can sometimes be just a large mess of emotions and thought that bear no resemblance to anything, and that do not necessarily mean something solid. Thoughts can sometimes spontaneously materialize in dreams, and it is very likely that the 'dark' dream guide was nothing more than how your dream chose to materialize your anxiousness or fear. Furthermore, although their dialog seems to have some sort of meaning behind it, I think that's nothing more than an ilusion. Their replies are only random thoughts that took form in sound.
Remember, things are only as powerful as people believe them to be. This applies to dream too, but in the literal sense: if you believe your dream guide is powerful, then he will be powerful. If you believe he's just a megalomanic DC on a power trip, then that's what he'll be. Taking power into your own hands is the easiest way to assume control over your LDs. I'm generally opposed to the idea of dream guides, because someone knowing more than you or having more power than you in an LD is completely phony for me. It's as if, let's say, a god chose one of his priests to guide him.

So, in conclusion: don't stress. Everything you experienced was just the product of your own anxiousness and chaos.