Recently, I had four gigs in four days. With a total of 16 hours of singing in those four days. And I caught a cold on the first of those four days.
The virus made my voice begin to falter on day 2. My throat grew more and more constricted on day 3, and by day 4 (my toughest day - four sets of belting rock tunes), I had to ration my voice like a backpacker rations food: Ain't no more coming, so better make it last!
This situation made me appreciate my many years of experience as a singer. In the early years of my singing career, I used to confuse volume and intensity of sound with intensity of performance, and would occasionally "blow out" my voice. I'd chalk it up to my inability to hear myself on the stage monitors, but now I know - after many years of performing - that good technique can help you out of that situation.
If you are a singer reading this, and you blow out your voice, try this trick the next time you can't hear yourself well: Challenge yourself to emote without pushing your voice, even if you aren't sure you're singing at the proper volume. Trust yourself! And let me know how it goes.