It happens from time to time.

Dreams like this can be troubling, but it most likely is just caused by your thoughts and how you felt before you fell asleep. I don't think you have to worry about dreams like this becoming normal, because if you've dealt with depression for a while without dreams that are related to it, then I doubt it will turn into a reoccurring thing.

Some of my dreams have a depressing side to them, but, like you, I generally don't have ones that relate directly to my depression. I can only think of 3 or 4 dreams from the past couple years, and believe me, they disturbed me just as much. They're not fun.