Billie Lourd grieves mother Carrie Fisher on 68th birthday

Billie Lourd lamented that she could not celebrate her late mother, Carrie Fisher, on what would have been her 68th birthday Monday.

"On my mom's birthday every year, I try to celebrate her as much as possible, but today I really wanted to celebrate her with her," Lourd wrote in a social media post.

Fisher, famous for her portrayal of Star Wars' Princess Leia, died in 2016.

"Some years my grief makes me feel the warmth of her love, some years it makes me angry, some years I feel numb but today when I woke up I just felt sad," she added. "I didn't want to celebrate, I just wanted my mom."

Lourd, who is also an actress, posted a photo of Fisher blowing out candles on a chocolate cake, with Lourd looking on, smiling.

She wrote that her grief "bodysnatched" her Monday, causing her to Google search the average age of death for women.

"Google said it was 80.2," she said. "My mom died when she was 60."

Lourd also discussed addiction in her post.

"I did everything in my power to help my mom get sober but sadly my mom couldn't ever escape her addiction," she said. "But while she was alive she always shared the ups and downs of that struggle with others in hopes it would help them escape their own addiction. As an addict, being open about the struggle is the only way through."

"And same goes for those of us affected by that struggle," she added.