Clarke, 34, announced he was retiring after England completed a crushing innings and 78-run victory in the fourth Test at Trent Bridge on Saturday to take an unbeatable 3-1 lead in the five-match Ashes series.
He will play the final Test at The Oval on August 20 before the curtain comes down on a distinguished career.
"My entire life has been about cricket. I've thought about the great game every day for as long as I can remember," he said in a column for the Sydney Daily Telegraph.
"I tried not to let emotion overcome me -- I've done too much crying over the years."
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Clarke, one of the best batsmen of his generation but plagued by injuries, knew the time was right to go, having reached 25 just six times in his last 30 Test innings.
"Once I got back to my hotel after day two (of the fourth Test) I spoke to my wife, Kyly, and then I went straight up to (Shane Warne's) Warnie's room," he said.
"Kyly and Warnie both gave me that support.