The former Bachelorette contestant said in December that “some days I can barely get out of bed,” due to the intense fatigue, fevers and full-body itching he was experiencing

Ryan Sutter is finally able to begin rebuilding his strength after battling a mystery illness for the last year.

The firefighter and former Bachelorette contestant, 46, shared in December that he has been plagued by an ongoing health issue that doctors have not been able to diagnose. His symptoms — "fatigue — sometimes almost paralyzing, deep body and muscle aches, fevers, night sweats, full body itching with no rash, headaches, neck and throat swelling, congestion, light headedness, nausea, and just general all around not feeling good" — started last February after he completed an 18-week training course with the Denver Fire Department and continued throughout the year.

Sutter explained that he had been tested multiple times for COVID-19, but they all came back negative, leaving him on a "frustrating" journey to try and figure out what was wrong. Now nearly three months after that post, the dad of two has some more positive developments — he's well enough to start working out again.

Ryan Sutter
Ryan Sutter
| Credit: Ryan Sutter Instagram; Presley Ann/Getty Images

"Doing my best to get back to my best," he posted on Instagram, along with a photo of himself lifting weights in a gym.

Sutter also thanked the gym owners for letting him use the space, and added the hashtags "#gettingstronger #onedayatatime."

RELATED VIDEO: Trista Sutter Grateful for Support amid Ryan's Struggle with Mystery Illness: 'This Year Is Hard'

Throughout the last year, Sutter has had his wife Trista and their kids, daughter Blakesley Grace, 11, and son Maxwell Alston, 13, by his side. In an Instagram post at the end of December, Sutter thanked Trista, whom he met and proposed to on the first season of The Bachelorette, for her support after he realized he needed to reach out for help.

"For me, health concerns brought on this realization, eventually forcing me to expose what I considered to be weakness. Once exposed however, weakness became opportunity," he said. "I was no longer alone in my struggle. My wife went on a mission, developing a medical strategy and path towards hopeful answers while at the same time leaving daily reminder notes to keep my spirits up. My family has rallied behind me, my friends have shown tremendous support and my colleagues a high degree of understanding and patience. For all of this I am grateful."

Sutter urged anyone who is also going through "adversity" to let themselves be vulnerable.

"As difficult as it may be, soliciting the help of others is a critical step in moving forward through difficult times," he said. "I appreciate all the help I have received and know that through it I am a better, stronger, more knowledgeable and more resilient man."