The Dragon Egg is gone!

When I finally reached the End in survival mode, I destroyed the End Crystals, and defeated EnderDragon, the Dragon Egg did not appear at the top of the portal! Just as I did not get nearly anything from xp, it was as if I had already defeated him before, but it was the first time, and I also noticed that the entrance portal to the end islands was already there before I even defeated the dragon. I was disappointed with this bug, because it was as if all the progress I've made in this world has been in vain.