"The depth of the pain is suffocating and bottomless without you every moment of every day," Lisa Marie Presley wrote

Lisa Marie Presley is paying tribute to her "beautiful" son Benjamin, who died by suicide on July 12, on what would have been his 28th birthday.

On Wednesday, the singer-songwriter, 52, shared a photo Benjamin from a previous birthday celebration alongside a heartbreaking note addressed to her son, whom she shared with ex-husband Danny Keough.

"My beautiful beautiful angel, I worshipped the ground you walked on, on this earth and now in Heaven," Presley wrote on her Instagram. "My heart and soul went with you."

"The depth of the pain is suffocating and bottomless without you every moment of every day," she continued in the caption.

Lisa Marie Presley
Credit: Lisa Marie Presley/instagram. Inset: Getty Images
Benjamin Keough
Benjamin Keough and Lisa Marie Presley in 2010
| Credit: Dave M. Benett/Getty Images

Presley — who is also mother to actress daughter Riley Keough, 31, and 11-year-old twin daughters, Harper and Finley, whom she shares with ex-husband Michael Lockwood — added that she "will never be the same."

"Please wait for me my love, and hold my hand while I stay to continue to protect and raise your little sisters and to be here for Riley," she wrote. "I know you would want that."

"Happy Birthday my sweet sweet Boy. You were much to [sic] good for this world," Presley added.

Benjamin's sister Riley also honored her late brother on social media, sharing an Instagram slideshow, which included photos of the two of them at her 2015 wedding to stuntman Ben Smith-Peterson and throwback pictures from their childhood.

Riley Keough
Benjamin and Riley Keough
| Credit: Riley Keough/Instagram

"Happy Birthday beautiful angel," Riley wrote in the caption, adding a heart and two storm cloud emoji, likely in reference to Benjamin's middle name being Storm.

On her Instagram Stories, Riley shared what Benjamin's former girlfriend, Diana Pinto, whom he dated since at least September 2017, posted for his birthday.

"Happy birthday my love," Pinto captioned a slideshow of her own, which featured several photos of herself and Benjamin, solo shots of Benjamin and an old video of his friends wishing him a happy birthday. "Not much to say just a really hard day, And isn't it ironic World Series Tampa Bay v Dodgers this year, I bet you're getting a kick outta that. I love you."

Presley's rep, Roger Widynowski, previously told PEOPLE that the star is "beyond devastated" over the death of her son.

"She is completely heartbroken, inconsolable and beyond devastated but trying to stay strong for her 11-year-old twins and her oldest daughter Riley," Widynowski said. "She adored that boy. He was the love of her life."

Presley and her son had a particularly close bond, and the pair got matching tattoos for Mother’s Day in 2009. Speaking to fans about it on Twitter in May 2012, Presley said it was "a Celtic eternity knot" that represents "eternal love and connection."

If you or someone you know is considering suicide, please contact the National Suicide Prevention Lifeline at 1-800-273-TALK (8255), text "STRENGTH" to the Crisis Text Line at 741-741 or go to suicidepreventionlifeline.org.