The 39-year-old finished fifth in the women's final on Sunday following a best leap of 14.48m.
"I have not slept in days," Aldama wrote in The Guardian. "I am heartbroken. What else can I say? It was, probably, my last chance to win an Olympic medal.
"I truly believed that I was going to be on the right side of that line, I believed that I would win a medal. When it did not happen it was so, so painful.
"I threw everything at it. For that I paid the price – landing on my shoulder in the sandpit, I hurt my shoulder and cut my elbow. All of these things are excuses. But there are no excuses, not really. I was not good enough and that is it."
Aldama won gold in this year's world indoor championships in Istanbul.