That's Dominick Reyes speaking openly and candidly about his four-fight losing streak ... after starting his professional MMA career with 12 wins -- many dominant victories -- which were good enough to earn the UFC light heavyweight a crack at the title.

That opportunity came in late 2022 ... and many felt the LHW star won the fight and deserved to be crowned champ. The judges didn't see it that way ... and Dominick's first loss turned into an extended losing streak.

In other words, he's been through hell -- and now 34-year-old Reyes is ready to emerge on the other side -- as he prepares to return to the Octagon On June 8 against Dustin Jacoby.

"I feel fantastic in all aspects," Reyes told TMZ Sports, saying, "Physically, I've been getting after it. Man, I've been getting after it. Focusing on the little things. Getting everything in order. Mentally, I'm rock solid again."

Of course, the losses came against the very best opponents in the world -- Jones (2020), Jan Blachowicz (2020), Jiri Prochazka (2021), and Ryan Spann (2022) -- but nonetheless, had Reyes scrambling for answers.

"I lost my way. I began questioning everything. Once you bring doubt in this game, you can't be successful. If you're doubting anything, you can't be successful. I was doubting," Dominick said.

"I changed camps completely for the next fight. I was like, 'I should have knocked them out. I should have done more.' So I went to a completely different team. And I tried to rebuild myself instead of refining myself."

"You can't just go to a new team and expect to be successful on the highest level. And then the following fight, it was like, 'I have something to prove to the world.' You know, 'I'm f***ing tough. I can go out there and slug it down with anyone.'"

"And literally my thought going into that fight was, 'I want to bleed.' Like, what dude? What's wrong with you, man? And that was my whole thought."

Dom even traveled to Connecticut to train with Alex Pereira and Glover Teixeira before realizing he was making a mistake.

"These dudes don't even know you. How on earth can you get better? All you're going to do is mess yourself up even more. So it was me constantly searching for something that I already had."

Reyes eventually concluded the answer was in front of him the whole time ... stick with the people who took you to the dance.

"I'm just grateful and happy for everybody in my life and everything that's going on. I know exactly who I am I know what I'm made out of. I know my abilities, you know, and I don't question it. I don't question it at all. I'm like, 'Hey I'm a f***ing badass, man."

Now, Dom's ready to remind everyone just how dangerous he is in the cage.

"I feel unstoppable right now," the 15th-ranked fighter said. "It's going to be hard to beat me going forward. It's going to be real hard to beat me."