You conked out really hard! [ after she drugged you ] So maybe that's why. Haven't you ever woken up from a nap and been really surprised that you were even asleep in the first place?

But you were sleeping for so long, I was starting to get a little worried. The library was going to shut and I didn't want us to get in trouble, so I brought us back here.

[ See? Perfectly normal. Totally reasonable. Nothing to be worried about. It's totally fine! ]

You can sleep in a little longer if you're still tired, you know. I don't mind!