An "irresistible" urge to sleep? What if it's resistable?

From Narcolepsy UK: "The most common symptom of narcolepsy is excessive daytime sleepiness (EDS), brought about by an irresistible need to sleep at inappropriate times throughout the day. "

I am trying to see if I could have narcolepsy, could you please help me understand this symptom?

Does the need to sleep have to be "irresistible" in order to count? What if you can resist it but it sort of feels like torturing yourself? Or what if your brain has just learnt to seriously zone out instead?

To be so tired that I can't process what's going on properly, is a common occurrence for me. I drift off into the limbo state anywhere - like I'll be at the dentist with my mouth open, or just today while *standing* in queue at the cashier...but I do that willingly. Or I unwillingly dissociate.

But to be falling asleep against my will? never.

PLEASE NOTE: I AM NOT ASKING FOR DIAGNOSIS I AM JUST ASKING TO HELP ME UNDERSTAND WHAT IS GENERALLY MEANT BY THIS SYMPTOM, AND PEOPLE 'S EXPERIENCE. THANKS