I cant leave the END!!!!

Every time I try to get out of the END I can't, I reappear in the END as if I were using the portal to the END. I also tried to get killed by the Endermans and I keep appearing in the END. I'm gasped and my whole game is spoiled. how can return to the Overworld.

When I killed the dragon it worked fine. then I went back a second time through the Elytra and I was able to come back fine. This is the third time that I go to the END and this time I can no longer leave. Not jumping on the retrun portal, no been killed So, what now?

I have also loads a backup copy and does the same. Help or my world and my work is for nothing and if so I stop playing minecraft forever.