No stranger to this occurrence here; gigging at least once a week for years now and this happens quite a few times a year. No other serious connected problems thus far, touch wood. As this only occurs during gigs, usually a good while into playing, I've been going with dehydration as the prime suspect. Over here (Japan) some "Sports drinks" have a bit of salt content ~ maybe an old wives' tale but I've found that these drinks are fairly effective.
As far as advice re next gig goes, plenty of water etc beforehand as well as during the show. Clearly, if it happens again over the next three or four shows it'd be sensible to see a medical professional but for the time being ~ forgive the possible pun ~ don't sweat it.
Best of luck Sir 🤞🏻