"What the f*ck am I doing to myself?" Casey Donovan gets honest about her health.

From her feel-good beach selfies to her ‘Big, Beautiful and Sexy’ philosophy, Casey Donovan is a beacon of body confidence and positivity for women of all shapes and sizes.

However, it seems the 27-year-old singer has been thinking about her physical health in great depth lately. In a blog post last week, Donovan shared her concerns about her weight and its impact on her quality of life.

“Tonight before I jumped into bed, I caught my reflection in the mirror. Standing in my bra and undies, I looked myself up and down and thought, ‘What the Fuck am I doing to myself?!'” she writes.

“I don’t want live like this anymore! I want to live a healthier life, try harder then what I am doing now! I have to! I don’t want to dig myself an early grave when the one thing I fear in life is death.”

Watch Meaghan Ramsay from the Dove Self-Esteem Project discussing confidence on Mamamia TV. (Post continues after video.)

The former Australian Idol winner also admits her desire to have a family has inspired her to change her lifestyle.

“What if I keep living the life I’m living and don’t do anything to help myself? What if I just keep putting the wrong foods in my mouth and don’t think of the consequences?” she asks.

“One day I want to have kids and be able to run round after them.”

Donovan then goes on to share a “conversation” between the various sides of her persona: Confidence, Anxiety, Negativity and Ego. (It’s a bit like the movie Inside Out.)

With a good dash of humour, she explores the delicate art of balancing body confidence with acknowledging the need to embrace a healthier lifestyle:

"Casey: My name is Casey Donovan and I am morbidly obese.

Confidence: But you’re Big, Beautiful & Sexy! ... Having a cheat meal isn’t the end of the world.

Casey: Confidence we both know it wasn’t a cheat meal… I was hungry, I wanted to eat. Sooooo… I put shit food in my mouth. Like I have done for the last 10 years.

Confidence: But look how far you have come!! ... You’re not as heavy as you were…

Casey: I may not be as heavy as I once was. But I’m still fat, aren’t I confidence?"

Donovan, who is currently starring as Joanne in a production of Rent, also details her anxiety about how her diet and lifestyle are affecting her body.

"Hey, did you guys feel that? Your heart, it did that fluttering thing again… HEART ATTACK TIME," her 'Anxiety' exclaims.

"Case, your heart is beating really fast.. Can you feel it? It’s getting faster! I feel sick… I think I need to vomit." (Post continues after gallery.)

Donovan explains that while confidence has enormously important, she hopes to recalibrate the meaning of her "Big, Beautiful and Sexy" outlook by making positive changes to her lifestyle.

"It’s wanting to be the best and healthiest that I can be! With a Big healthy heart, A Beautiful healthy life and A Sexy love for the healthier, happier me," she writes.

"I keep letting Ego and Negativity get the better of me. It’s time to get real about life, it’s time to not be lazy with what I am putting into my body and reward myself with a new look on life and get out there and make that change."

Can you relate to Casey's post?