Go to the library and fetch 20 Master Plots by Ronald B. Tobias. Reading that will soothe your fears quite nicely. Or, choose a basic sci-fi or fantasy idea that you are currently not using, and make a list of all of the works that have used that idea. Once you see that 50 different books/tv shows/movies have all covered the alien symbiote idea and yet 40 of them were fantastic and all of them were very different in the end, it might help you realize that your robot love story is unlikely to resemble Battlestar Galactica only in superficial ways. For example.