The 46-year-old was dismissed by the Football Association on August 20 after a 15-year spell in charge of the side.
During that time Powell guided England to the 2009 European Championship final, but a poor showing at this year's tournament in Finland sealed her fate.
When asked if she knew that her job was in jeopardy, Powell told BBC Sport: "No, to be honest. We just didn't perform. It was not through lack of effort on the players' part.
"I am disappointed, but I have accepted it and have to move on. I need some time to recharge and see what opportunities come up."
Assistant coach Brent Hills has taken charge of England as the FA looks to appoint a new manager.