Well, if it were my dream, I would think these things (but note that symbols can vary from person to person as Dark suggested):

- Dark water = negative emotions (fear, anger, hatred, rejection, shame, etc. - could be any of them)

- Crocodiles = cold-blooded people that may lack empathy

- Falling into a pit = no way out, feeling of being trapped

When we are children, we are stuck and completely dependent upon others at home and school. Maybe you felt there were people in your life who did not have your best interests at heart [crocodiles]. Maybe you felt you had no way out [pit] and their attacking you was inevitable. Maybe they would even devour you [or your sense of self].

I hope this is helpful. Good luck!