Is there any other way to gain stamina?

[R.Rokku_u]

I have one save and i didn't do any of tests but whenever I try to do one to not get kicked out from school I can't because I used all stamina before and now I am locked with expelled "ending" (I don't want to start again because I have 130/150 love with Kyoko)

[Shoujo City]

Sleeping is the only way to restore energy in the game.