The athlete won the gold medal with victory in the 800m, one of 29 gold medals won by Team GB athletes during the games.
"This has completely surpassed anything I could ever dream of," Ennis told Heat.
"It's one thing winning an Olympic medal, but it's another doing it on your home country.
"I was completely taken aback. It was really overwhelming. There was so much positivity in the stadium."
Asked about her post-Olympic plans, Ennis said: "I'm definitely going to relax, eat lots of rubbish food and have a few glasses of wine."
London 2012 Olympics - Every Team GB gold medal photo gallery:
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