There's a joke there...
she needs a really good... shall we say... pounding.
(And I don't mean violence.
)
She's probably stressed because she hasn't done the grades yet. She's not being smart if that's the case. But she shouldn't have snapped at you like that. She should have explained what was going on that prevented her from giving you what your current grade was at that moment. (Likely that she hasn't put the grades in yet... or even graded some things.) Trust me when I tell you that teachers definitely do NOT have it easy.