There are a few general guidelines for working musicians: stay in the pocket, start in tune, be sober enough to play, wear pants, learn your parts. Of course, these are simply guidelines, so should one fail on a few of these, no big deal. But there is one long-standing rule that will put your gig in peril if broken: the show must go on.

Jay Leno tries his hardest to look friendly while keeping his distance from me.

In keeping with that rule, I recently playedThe Tonight Show with Jay Lenoin a near delirium of fever after having spent three hellish days shivering, sweating and doing lots of other scatological stuff you don’t want to read about. It may have been food poisoning, or perhaps the combination of sleep deprivation and stress had left me vulnerable to a nasty virus.

I had been very busy. Eleven days before Leno, I played the Academy of Country Music Awards in Vegas with Laura Bell Bundy. After the show, we played the after-party, and then I spent a few hours staring at the hotel room clock before schlepping to a 5 a.m. lobby call to catch a Monday morning flight to New York. Tuesday meant another 5 a.m. lobby call for an 8 a.m. slot on Good Morning America, and then it was back home for a few days of studio work and a Friday evening bar gig until 2:30 a.m.

On Saturday, my wife, Megan Mullins, and I rose early, drove to Muscle Shoals, Alabama, to play a Randy Owen benefit show with Randy and a slew of other artists that we backed up. After the show, I drove us home arriving at 3:30 a.m., giving me an hour to get Megan to the airport to catch a 5:45 flight to L.A. where she had a gig playing in the house band on American Idol. After a day of near fatigue melt-down, I then stupidly took a last-minute gig in downtown Nashville that Sunday night from 10 to 2:30 a.m. I began to feel sick during the gig, and by the time I got home my head was pounding and I was sweating profusely. By the next morning it felt like I had a mild case of the Bubonic Plague.

I spent a delirious Monday sprawled on my bathroom floor praying for a quick recovery or a swift death. After choking down some long-expired muscle relaxers and waking on Tuesday to more gastrointestinal violence, I summoned all my strength to respond to some pre-Leno emails. Management apprised me that the song had changed. I had to email the band the details, cancel our horn guys and make some changes to our stage plot. At that point I was on autopilot, not sure what I was doing, and tried to introduce some food into my system before the next day’s flight.

I no longer fear hell after experiencing that Nashville to Dallas to Burbank flight, all middle seats, sandwiched between unsuspecting commuters. I would rather sit next to a drooling Ebola monkey than that sweaty version of me, and I was living proof that you should always take Airborne with you when you travel.

Once we arrived at the studio Thursday morning, I was so pumped to be on Leno that I began to feel okay. But when I picked up my guitar during soundcheck, it felt foreign. I rarely go too long without holding a guitar but there had been none of that during my three days of porcelain hugging. I couldn’t remember what key we were in and was never sure I was in the pocket. The intro is all me and drums. When our drummer, Nioshi Jackson, asked, “You need a little more hat in your mix, J Boh?” it crossed my mind that I could really butcher this thing.

Between soundcheck and the show I shut down in our dressing room until I had to get dressed and go to makeup, where they added some color to my deathly pallor. About 10 minutes before we were to go onstage, I felt that now familiar knife-like stab in my stomach. I went down the hall, out of the studio and found a bathroom far, far away from the Leno camp. I made it back to the stage with five minutes to spare. It occurred to me that I could quite possibly lose it on Leno—prob- ably not a first, but not anything I cared to do. Remembering that somebody once told me, “If you can laugh about it later, you can laugh about it now,” I smiled and walked on stage.

Remarkably, the show went off without a hitch. Post show, Laura Bell and I went into the sound room and listened to the final mix; I liked our live version of the song, “Boyfriend,” better than the album version. While there, I got some great tips from Charlie Bouis, Leno’s live sound engineer, about mic placement. (He placed a Shure SM57 straight on the grill, pointing at one speaker where its cone meets the coil, and a biggish Sennheiser I didn’t recognize dead on the second speaker. Charlie then added a bit of 1kHz sparkle to both mics.)

In short, though it was hellish, I’m glad I made the gig. And while this column may be a little too much information, it shows the ugly side of the business that many don’t see. Just remember: you can break any number of guidelines, but never break the rule.

John Bohlinger is a Nashville guitar slinger who works primarily in television and has recorded and toured with over 30 major-label artists. His songs and playing can be heard in major motion pictures, on major-label releases, and in literally hundreds of television drops. Visit him