Well you have about 5 more days, you are aware it takes 28 days to hatch? I would just keep incubating and see, don't count it out until after the incubation period.
I don't think at this point you can tell, if it's all dark that's good, keep incubating it, and hopefully on day 28 it will hatch, if it doesn't by day 30 I would get rid of it.