If Sage Northcutt didn't look like himself at UFC on FOX 18, he didn't feel like himself either. Northcutt, the 19-year-old prospect who suffered the first loss of his professional career on Saturday night in Newark when he tapped to an arm-triangle choke at the hands of Bryan Barberena, revealed Monday on The MMA Hour that he was forced to overcome a sudden bout with strep throat late during fight week.

"Two days before my fight, I had a real bad relapse of the strep throat and I had to go to the emergency ready clinic," Northcutt explained. "The UFC had to take me, then [a doctor] with the UFC had to write a prescription for more antibiotics, stuff like that. So I really couldn't explain how I felt out there. I felt really horrible."

Northcutt said the battle with strep throat was his third over the past four months, and his symptoms worsened as fight night drew closer.

"I've never felt like that ever before," Northcutt said. "Not just the breathing. It felt like I couldn't concentrate. I wasn't my normal self. I was having a real hard time hearing. Like, you can imagine if you fly on an airplane and your ears get stuffed up where they have to pop? It felt like that but times two or three, where I couldn't even hear my coaches, what they were saying. Even face-to-face, I couldn't hear anything.

"Coming up in the week for the UFC, I always try to keep a smile on my face and act like there's nothing going on, so that way no one would know that I was even sick or anything like that. The UFC knew I was sick because I had to go to the emergency clinic. But really, I was just laying down in bed and sleeping the whole time coming into the event, besides going out and doing the media that I got do to and had to do for the UFC."

Northcutt was initially slated to fight Andrew Holbrook in a lightweight bout at UFC on FOX 18, however Holbrook withdrew eight days out from the event and Barberena was tagged as a replacement. Northcutt said the decision to change the fight to welterweight was made because Northcutt was starting to feel the warning signs of strep throat, and he and his coaches figured that draining his body to make the lightweight cut while sick would leave him unable to fight.

Northcutt was showered with criticism online in the aftermath of his loss, both from fans and his fellow fighters. While a few fighters, like Donald Cerrone and Sergio Pettis, offered words of support to the teenager, many of the Northcutt's UFC stablemates disparaged the young fighter's heart and labeled him a quitter for tapping to Barberena's arm triangle from half guard, rather than side control or full mount -- the positions where such a submission is generally competed. Northcutt, though, said his poor health played a large part in how things played out.

"It wasn't the fact that I was panicking. I felt very calm," Northcutt said. "The thing was, having a hard time breathing and having a mouthpiece in ... when he was on top of me, having his shoulder, I guess, in my throat for that -- I know it wasn't like a traditional head and arm choke from side control where you get to apply the same kind of pressure, but just being able to have your jaw shut and then trying to breathe through your nose for this time during the fight, I was so congested, to tell you the truth, that I couldn't even breathe, much less stand up really.

"That's why I wasn't able to move the same, wasn't able to kick the same. What I wanted to do and what I thought in my head about doing out there, I wasn't able to actually act it out and do it because my body wasn't able to keep up. It was like breathing through a straw. That's what it really felt like. So down there in that position, even though it may not have been the best locked in hold, I was having such a hard time breathing that it was just as tight as what it might have been if I was in that kind of position if I wasn't sick, if that makes sense."

Despite his illness, Northcutt said the notion of pulling out of the fight never crossed his mind. With his unbeaten record no longer intact, he ultimately chalked up the experience as one that will make him better in the long run.

"With the UFC, having a fight like that and having to reschedule a last minute thing, moving up a weight class, you're there to fight. So, that's my job," Northcutt said. "You don't want to pull out of the fight when you have so many people and fans and friends, everybody, and especially the UFC being my job, to be able to go out there and fight for them, you don't want to pull out and have that ruin the outcome of the event for the amount of people that came to support you and watch you and everything. That wouldn't have been good, and obviously you never want to pull out of that. At least I wouldn't. So, going out there and fighting, I thought I could do it.

"I felt like I let everybody down and let the UFC down. I let myself down."