Chill, do not worry. It can often take a bit for eggs to hatch, sometimes 23 days. Also, did you expose the eggs to any sort of cold area? Because if so, you gave the eggs a temperature shock, which might have killed the embryo. Try and put the eggs over the flashlight of your phone and see if the eggs have an embryo inside. Are you even sure these are fertile eggs? Hope this helped.
You put eggs under the hen that were ready to hatch? Is she staying on them?
Are you counting day 1 as the day incubation started? That should be day Zero. Even if you counted from 0, taking an extra day or even 2 isn't unusual.