Note: This is not a suicide attempt. Just putting it out there now.
 
***  
It started the day she said yes to Tempest.
 
They had been tip toeing around the subject but when the question was asked, Twilight felt overjoyed. She didn’t think she would be Tempest’s type.
 
She was so strong and able so why choose her?
 
But regardless, she said yes and thats when it started.
 
The bad thoughts. The niggling seeds of doubt planted by her own subconsciousness.How could she do this? Didn’t she love Celestia? How could she betray her like this?
 
She knew it was ridiculous and drowned them out, basking in the shared joy her friends gave her in response to Tempest and her finally hooking up.
 
Yet the thoughts didn’t stop. Whenever she let her guard down, another one would pop up. Tearing her down, breaking her short-lived joy. The guilt she felt, even as she knew it was unwarranted, had left her immobilized many times. There were times she’d be standing at the edge of her balcony, those terrible thoughts echoing in her head, telling her it would only take a second. One second and all the bad feelings would end. Then she’d pull back, wanting to scream but clenching her teeth tight.
 
No, she couldn’t do that. She refused to give in but… she couldn’t stop the thoughts, the ideas, from taking over. She had to do something before she forgot why she kept resisting.
 
There were medicines for it, right? Yes, there had to be. Just a few sips and the bad thoughts would fade and she could get back to normal. But they kept coming back. Every time she felt cured, it reared its ugly head again, taking with it all her happiness.
 
So she took more and more medicine. Just to make it stop.
 
But one day, she took more than she needed and got closer to that edge.
 

 
Twilight wasn’t in the best place after Celestia’s disappearance/assumed death. As the wife of the ruler and the hero of Equestria, she felt like she had failed when the news came in. To make matters worse, many ponies blamed her for Celestia’s fate. It was only after many years of support and care that she began to open up again and try for more.
 
The day she was asked out by her captain of the guard, Tempest Shadow, she felt like she could live past all her grief.
 
Then the guilt of all that began to nibble away at her self esteem. Part of her felt like she was doing a bad thing by moving on and it led to her spiraling back into her depression. This time, however, she turned to medicines rather than her friends, as she didn’t want to worry them again.
 
In this pic, she took too much and was hospitalized. She was pregnant with Nova at the time and deemed unfit to carry the child as she found to have mild suicidal tendencies. In reality, she truly didn’t want to hurt herself or her child. She really just wanted to stop feeling dead inside.
 
Note: This time, I took some of my own experiences in writing this. I can’t say I have depression but there are times when I have bad thoughts and this is how it is for me. Casually staring at cars as they rush by contemplating how I could get hit or the like. As for the drugs, she has prescribed the drugs, she just took too many one time.