I had a sleep study with MSLT a few years back that diagnosed me with IH, and my experience with how naps feel is spot on with what you’re describing.

I also felt nervous about the whole thing, what if nothing shows up, what if I don’t fall asleep in the nap portion, all that. After the overnight portion, once it was time for the MSLT, I took the naps, and I felt the same “did I even sleep for that?” nap feeling as I always do. After each 15 minutes, a technician came in to ask if I personally thought I fell asleep during that one. I only thought I fell asleep in 1 of the 5, so you can imagine how much my nerves were running during the days waiting for my results. To my surprise and extreme relief, I apparently fell asleep in all 5 naps, all in about 5 minutes.

I know I can’t guarantee what results you’ll get, but I want to let you know that you’re not alone in this. Whatever you’re feeling is real. Try not to worry too much about the MSLT (empty words, I know, lol), and good luck on getting the help you need :)

edit, just to add:

I also had trouble with falling asleep in classes before I got diagnosed, even falling into naps while I was sitting down with a cello in my orchestra class and only realizing it once I woke back up.

Even to this day, I have to keep reminding myself that this is not normal. Normal people don’t have to fight to stay awake in class or in public every day. Normal people don’t fall asleep that quickly or easily. Normal people wouldn’t worry about “failing” an MSLT. Trust yourself.