Simpson gave fans a look at her celebrations on Sunday on her Instagram Story, sharing her reaction to the gifts she received from Johnson and her older children, 7-year-old daughter Maxwell and 5-year-old son Ace.
“Mother’s Day 2019: fresh milk and hormonally crying reading my Mother’s Day cards,” the 38-year-old captioned a photo of cards, flowers and gifts from her family.
She then offered a close-up of notes from Johnson and her kids, with her husband's message reading, “Dear Jess, You have literally taken motherhood to the next level. You have given us three kids and I could not be more grateful or in awe of you. You make every one of my days special. I love you with all my heart. Love, Eric.”
Simpson also posted a photo of a card from her children.
“Dear Mom, You could not be more beautiful, more funny, more loving, more fun,” the note read. “We love you to infinity and beyond and tie a couple loops around the moon on the way back and then back to your heart. That’s how much we love you. You are the greatest mom in the universe.”
Simpson also shared her own Mother's Day tribute with a shoutout to her sister, Ashlee Simpson, and her mom, Tina Simpson, posting a Polaroid photo of the trio posing together.
"Happy Mother’s Day,” she wrote. “Ash and I are strong women because we had the strongest raise us. I love you [Tina Simpson]!"
Since becoming a mom of three, Jessica has continued to share her journey as a mom with her fans, most recently giving them a look at her postpartum workouts.
"Just stretching it out in my rubber corset," she captioned a recent photo of herself wearing a rubber corset and stretching to touch her toes. "The joy of postpartum."
The singer told PEOPLE that the transition from two kids to three hasn't been easy, but she and Johnson are doing their best.
“Three is challenging. We are trying to get into the groove and make sure all three kids are getting equal attention... it’s more than a full-time job right now,” she said. “The other night, all three kids were crying at the same time, so I just joined in! Ha!”
“[Birdie] makes our family complete,” Jessica added. “Someone once told me to keep in mind that everything is a phase with infants and kids...trying to remember that fact, and celebrate the small victories.”
Photo Credit: Instagram / @jessicasimpson