This is something I have to deal with too. I'm still figuring out how to have these conversations.
Sometimes it's helpful to put N in context with other (better known) diseases, like Epilepsy, Diabetes, MS, and arthritis. I'll say it is a neurological disorder with no known cure, and only partially effective treatments. It affects all areas of life and it can be very debilitating. I recently told an acquaintence that it's like going 3 days without sleep (and not in the party sense), all the time. This in spite of the fact that I am fairly healthy, young (in my 30s), and following the suggested guidelines for treatment and lifestyle.
Here's some more sharing, in case it's useful to you:
I was diagnosed with narcolepsy in the summer of 2009. I've had it since at least my early teens, but didn't realize it till a month or so before I went for testing.
Depending on my mood, level of sleepiness, and cognitive functioning, I feel anywhere from bemused to enraged when I think someone isn't taking me seriously. If I'm having a sleep attack or in a total fog, it's extra hard to have perspective. All my resources are taken up by the need to lie down, hide, or just stay upright if the first two options aren't possible.
I've found that it helps to "come out" to people before I get an attack (which you may be doing already). If I'm going somewhere or meeting friends, family, or colleagues, I try to give them a heads up at the beginning of, or before, the outing.
Work environments are tricky. I shared with coworkers when I was working full time at a medium sized company. I let my bosses and human resources know when I was getting tested, then diagnosed, then coping with treatments and lifestyle changes. I had both positive and negative experiences. Many coworkers were kind and open minded. If I were to do it again (I'm no longer working there), I probably would hire a lawyer to help me know my rights and provide me with a sense of legal protection/recourse when HR balked about accomodating me. (I had to go on 7 weeks of short term disability, I needed nap breaks and a place to take them, etc...)
I don't mean you necessarily need to hire a lawyer to cope at work. But the issues you are dealing with are quite real, legally, emotionally, socially, and of course physically. Know your rights. Know that people may or may not be able to comprehend quickly (or ever) what life is like for us. In many respects, narcolepsy is an invisible disorder/disability. In general folks are ignorant about it.
I tend to be very open about having narcolepsy. I encounter a lot of curiousity. Most of the time I'm the only narcoleptic people have knowingly talked to. They are still processing the information (lol This can take a while). I think that in an attempt to relate to me, or understand it for themselves, people can be--or seem to be--dismissive, incredulous, or insensitive. Their reaction is a reflection of how they view themselves, too.
I prefer to call N a neurological disorder, rather than a sleep disorder. I don't just get sleepy. My brain regulates awake, sleep, and dream states--and the transitions between those states--differently than it does in 99% of humans. Appetite, anxiety and stress management are also connected to this part of the brain. There is a strong correlation between REM activity, creativity, and problem solving. I like to think of it as more of a mutation than a defect.
That said, I definitely have a hard time functioning and living on my own in mainstream US society. I hope it gets better as I learn to cope better and leverage the unique way my brain works.
Good luck. You're not alone.
I wasn't sure whether to put this in Daily Living or Relationships, so I stuck it here; hope that's okay.
My diagnosis of N is relatively new, and it has been hitting me much harder lately, so having to deal with it is becoming a larger part of my life. The problem I've been facing lately is that people don't take me seriously. When a sleep attack is coming on, I try to just go hide away somewhere, but sometimes other people are around and I have to communicate to them what's going on. I say that I need to sleep, or I need to go take a nap for a few minutes, and they're just like "Oh, yeah, me too. I could totally go for a nap right now!" or "Yeah, I'm so tired, yawwwn." and then they kind of expect that I'm just commenting and don't understand/realize that NO, I need to go sleep like right now.
I've braved it a few times and told co-workers that I have narcolepsy, and they seem like they don't really believe me or something. I think part of it is because it has really only been hitting me hard in the past few months. I also spend a lot of time alone at work, so I am usually able to nap without anyone knowing. That, and also, in the past, I was able to fight back the sleep attacks and stay awake, if barely. People don't see me falling asleep randomly, so they (appear to) think that I'm just making excuses for wanting to be lazy or slack off on work.
Do you guys face this too? How do you get it through to them that this is a real ailment and that you actually have it? I'm feeling quite discouraged. 
