In a candid blog post on her website, Kardashian, 36, said focusing on fitness to lose the baby weight from 1-year-old son Reign has helped her stay strong since the couple's July breakup.
"Everyone deals with hard times in their lives differently. I'm generally not a nervous person but I get anxious. I also get nauseous and feel like I can't eat when it is really bad, but I force myself to stay healthy," she said. "One thing I've found that really helps is working out. I try to exercise 5 days a week. I usually start with a quick run or jumping rope to warm up. I have to do something fast to really kill it. And I definitely need good music."
"People are very quick to judge others by appearances but you truly don't know what someone's motivation is or what is going on inside them," she added. "For me, exercise is as much about my body as it is about calming my mind."
The mom of three and Disick, 32, ended their nine-year relationship after he was photographed partying hard with another woman. He's since been treated for alcoholism in rehab, and Sunday's episode of Keeping Up with the Kardashians showed him tearfully apologizing to the famous family for his wild behavior.
"If I didn't have those kids, I would kill myself," he said. "But I have them and I'm going to be here and I'm going to make it right for them. I just hope that somehow … God can like, give me a chance or us a chance at this."
RELATED VIDEO: Scott Disick Apologizes to the Kardashians
Kardashian's sister Khloé also found working out to be therapeutic after her own breakup from estranged husband Lamar Odom.
"When me and Lamar were having issues, I decided to channel my energy into working out," she said told U.K. Cosmopolitan Body in April. "The gym was my only refuge."