Kelley Flanagan has revealed some very personal information.

Also, unfortunately, some very troubling information.

On Monday, The Bachelor alum jumped on her Instagram page to announce she had tested positive for Lyme disease after she felt "something was a little bit off."

Flanagan, who competed for Peter Weber's heart on the aforementioned ABC reality show, turned emotional right away while confirming this diagnosis to followers.

"I'm not having the best day today," Kelley said to open her emotional video. "I always talk about health and how I just always felt like my body's been so much more sensitive and super reactive to a bunch of things."

Continued the former contestant:

"I'm pretty honest with you guys about what's going in my life.

"I just got the results back and I tested positive for Lyme."

The Chicago-based lawyer went on to say that she decided to get tested because her two brothers suffer from the same disease.

"A lot of their symptoms sounded really similar to me," she explained. "Because I've always just had something off since I've been young."

Flanagan, you may recall, did not technically win Weber's season of The Bachelor.

But she got together with the polarizing pilot several weeks after he dated two other suitors from his season, coming very close to moving in with him even.

The couple split in late 2020... then got back together a short time later... and then Kelley said Peter cheated on her.

A LOT.

"It ended really badly," Flanagan said on a podcast early this spring, adding:

"I essentially went off on him. I ended up leaving New York and going to one of my girlfriend's houses and hanging out with her.

"He texted me, I didn't respond and then found some news out that I wasn't happy about."

Back to Kelley's health update, though.

"It's a blessing and a curse because now I can target why I feel off so often but also means several different lifestyle changes and extensive research on how to help/hopefully cure this!" Flanagan wrote in the video's caption.

"I know this is going to be tough for me seeing what my brothers have gone through mentally and physically.

"But I'm going to put so much of my time and energy into figuring this out and combatting this."

Kelley concluded her message by saying she knows the diagnosis is "not the end of the world."

Doesn't mean things won't be a challenge going forward, however.

"I'm trying to stay positive," she said.

Thankfully, Flanagan has plenty of support in her battle.

A number of Bachelor Nation co-stars came out with positive messages after Flangan shared her news.

"Love I'm so sorry! Must be a relief to finally have an answer to start off from! Know you are surrounded by so much support! You will only become stronger from this," wrote Kendall Long, for example.

Added Taylor Blake:

"So sorry to hear about this, I have no doubt that if there’s anyone who can beat it, it’s you. Sending lots of prayers your way."