Khloé Kardashian welcomed her first child, daughter True, in April of last year

After her daughter True was born last year, Khloé Kardashian quickly learned that her post-baby weight wasn’t going to disappear.

“In my head I felt like I would push the baby out and then I’ll be skinny again,” says the Keeping up with the Kardashians star, 35. “Then you get home from the hospital and you’re like, ‘What?’ It’s a big shock.”

Kardashian, whose hit show Revenge Body returns in July, was ready to get back into fighting shape.

“As soon as I got clearance from my doctor, I was [in the gym],” she says. “I was so excited to start working out again. Mentally I was there. But physically, I couldn’t do it. I was out of breath. I didn’t know how I was going to get to my end goal.”

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But rather than beat herself up, “I took it really slow,” says the reality star. “I did it day by day. If I could get through that workout, I did. But you’re not going to get it back in a day.”

Continues Kardashian: “I was really proud of myself for not being as hard on myself. On Kylie’s 21st birthday I was in a crop top and high-waisted pants. I wasn’t at my thinnest at all, but I was so proud for getting to where I was at that time. I was like, ‘I’m going to show this off!’ ”

And ultimately, Kardashian whose daughter True is now 14 months old (True’s dad is Kardashian’s ex, Tristan Thompson) says “we have to be kinder to ourselves.”

Continues Kardashian: “It took nine months to gain the weight, give yourself at least a year to take it off. You have to adjust. And you’re juggling with a baby and your life and trying to do those moments that are about you. You have to be kind and learn how to balance it all.”

Revenge Body premieres Sunday, July 7 at 9pm ET/PT on E!