Rumer Willis hit by mystery stomach illness

Rumer Willis hasn't been able to enjoy the success of her new movie Once Upon a Time in Hollywood due to a mystery illness, which has left her "exhausted, overwhelmed and broken down" for much of August (19).

The actress shared a makeup-free selfie of herself looking poorly on Instagram, along with a note about her condition, explaining she has hit a health low.

"This was me yesterday," Rumer wrote. "I had just gotten off the phone with my sister after having a full little kid meltdown. Sobbing about how I was so tired and feeling helpless.

"I have been sick almost the entire month of August that started with food poisoning to then an unknown stomach problem where I haven’t been able to eat because when I do it feels like my stomach is on fire to the flu that turned into a sinus infection. I felt helpless and scared and so utterly overwhelmed. I felt like time was just drifting by and I was trapped in a body that didn’t want to work with me."

But Rumer, who portrays actress Joanna Pettet in Quentin Tarantino's new movie, insists she's beginning to feel better: "I woke up this morning feeling a little better and feeling much more integrated in myself because I was no longer at war within. I am by no means 100% yet but getting there."

She ended her post with a challenge for her fans, adding: "I encourage you as you move forward with your day, week or even month - allow yourself to let go of the control of the outcome, control of the expectations of how it should go or look, and let go of whatever story you are making up about yourself if it doesn’t turn out the way you planned," she shared. "It’s all happening for you, not to you."