I had a friend with narcolepsy. She did not fall asleep all the time like the severe cases you see on TV. But she would be tired in daytime and have a strong tendency to fall asleep if she wasn't doing anything. She was diagnosed even if she did not have cataplexy. She had bad vivid dreams and sleep paralysis with hypnopompic hallucinations though, which is common with narcolepsy.

No one knew she even had it. She hid it quite well.

It does not seem odd to want a sleep study. I hope someone take you seriously to do so or at least look into this. It is easy for them to say all people get tired so it is really important to actually describe how tired you get and in what situations and lot of examples. That might make them understand.