Amber Smith is fighting a battle that she's sick and tired of being shamed for.
She wrote: "It disgusts me that so many people are so uneducated and judgemental over the topic.
"They say that one in three people will suffer with a mental illness at some point in their life. One in three! Do you know how many people that equates to worldwide?!
"I've been battling with anxiety and depression for years and years and there's still people that make comments like 'you'll get over it', 'you don't need tablets, just be happier', 'you're too young to suffer with that'."
Smith also shared a candid 'before and after' image to highlight that you can't always see mental illness on the outside.
The first picture depicts what she would usually showcase to the world on social media. It shows Smith dressed up, with makeup on and filters galore. She describes the photo as showing "the normal side" to her.
The second image shows Smith with watery eyes and holding her face. She is clearly very distressed.
She said the second image was taken shortly after suffering from a panic attack caused by anxiety, and then added: "[It is] also the 'normal' side to me that most people don't see."
Smith penned the post to the "small-minded people" that think she looks physically "fine" and therefore can't possibly be battling a mental illness.
She added: "Someone actually said this to me one day 'aren't you too young to be suffering with anxiety and depression? What do you actually have to be depressed about at your age?' Wow, just wow."
Ending on a positive note, Smith said she is thankful for her family and friends who have the patience to support her, and encouraged others to seek help and support instead of suffering in silence.
To conclude, she wrote: "It costs nothing to be nice to others. Don't bully others, don't put others down and the hardest one of them all - as we have all done it at some point - don't judge another person.
"We're all human regardless of age, race, religion, wealth, job. So build one another up instead of breaking each other down."
The brave post has been shared more than 2,000 times and many people have praised Smith for opening up about her struggles.
Mathew Cliff wrote: "Fair play for sharing this! A lot of young people need role models like you!"
Laura Michelle Hansom added: "You're a very brave, strong lady. It's so nice to see someone speak out about it. I've suffered from depression and anxiety for almost six years now (from the age of 20) it's such a taboo subject.
"Lovely to see it being spoken about, it's also nice to know you're not alone."