Seconding for for ADHD and narcolepsy. I had a sleep study done a few years back that came up borderline positive. Doctor had me try a few meds out but the one that really stuck was Vyvanse (basically a slow release pro-drug of Adderall). Suddenly I’m not having sleep attacks every time I sit down, or even feeling like my head is made of bricks.

I grew up in a family that didn’t believe in ADHD so I would cope with excessive amounts of caffeine. It’s definitely worth looking into if you have the slightest suspicion.

Also don’t get too caught up in passing the MSLT. Personally, I think it’s barely medical science, but it’s a part of getting a diagnosis and some insights into how your brain is (or isn’t) sleeping.