Hello, minervajane and welcome! What you call prognostic dreams some people call that precognitive dreams, and the subforum where we discuss those is Beyond Dreaming. Also it sounds like for some of the weird dreams that you cannot understand, you may be interested in posting in this section of the forum as well: Dream Interpretation

Most of this site is geared toward people interested in lucid dreaming, becoming aware in dreams and controlling dreams while knowing they are dreams. However, some of us are interested in understanding nonlucid dreams better, and of course the two do not need to be mutually exclusive, so if you want to check out how to recognize dreams as dreams in addition to understanding subconscious symbolic dreams better, I think that is a good approach - but then again, I may be biased in an open minded sort of way.