Carrie Underwood gave birth to her second child, son Jacob Bryan, in January


Carrie Underwood is opening up about the pressure to “bounce back” after giving birth.

The country singer welcomed a second son, Jacob Bryan, on Jan. 21 with her husband Mike Fisher, and on Tuesday she opened up about feeling the “difficult” changes in her body after giving birth.

“I’m going to be honest, ‘bouncing back’ after having Jacob has been much more difficult than after I had Isaiah and I’ve been pretty hard on myself lately,” Underwood, 36, wrote. “I go into the gym and I can’t run as fast or as far. I can’t lift as much weight or do as many reps as I could a year ago. I just want to feel like myself again… for my body to feel the way that I know it can.”

“As I was working out today, I realized that for the past 11(ish) months, my body has not belonged to me,” she continued. “It was a perfect home for Jacob. And even now it belongs to him every time he drinks his milk. As I prepare for red carpets and for life on tour, right now I make a promise to myself to start appreciating what my body CAN do and stop focusing on what it can’t.”

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Underwood finished: “I promise to stop analyzing every angle and every curve and every pound and every meal. I’m going to keep staying the path because it is a journey and as long as I’m always working towards my goals, one day I’ll reach them. I’m going to take it day by day, smile at the girl in the mirror, and work out because I love this body and all it has done and will continue to do!”

The new mom of two revealed that she had given birth in an Instagram post on Jan. 23.

“Jacob Bryan Fisher entered the world in the wee hours of the morning on Monday … his mom, dad and big brother couldn’t be happier for God to trust them with taking care of this little miracle!” Underwood wrote alongside a photo gallery of herself, Fisher and proud big brother Isaiah Michael, 4, with newborn Jacob.

“Our hearts are full, our eyes are tired and our lives are forever changed,” she continued. “Life is good…”

Mike Fisher with sons Isaiah and Jacob
| Credit: Carrie Underwood/Instagram
Carrie Underwood with son Jacob
| Credit: Carrie Underwood/Instagram

Earlier this month, Underwood celebrated her 36th birthday with some love from her “boys,” as Fisher marked his wife’s big day with a sweet message on Instagram also attributed to Isaiah and Jacob.

“Happy birthday babe! You’re an incredible wife and mom!” Fisher, 38, captioned a selfie of the couple. “Us boys are so grateful for you! Love you lots.”

After welcoming Jacob, a source told PEOPLE that the proud parents are in full nesting mode in their new mansion just outside of Nashville.

“They’re total homebodies,” the source said. “They rarely leave their home at night and love the outdoors and often go for walks.”

“Carrie lives a very quiet life. They take Isaiah fishing, to the zoo and to farms so he can learn about animals,” the source continued. “They very much live a farm life and seem to love it.”