Grade?!?!Help Needed...

Okay so I'm taking AP Spanish and I have a 91% (a.k.a A-) in that class and I just got a 75% on my last test and it is weighed at a 50.0 do any of you guys know what my grade would be after that? I don't want to fail this class because I hope to go into college to be a Spanish teacher but I need my grade to be good. Any ideas of what my normal grade will be brought down to?I am really nervous that'll make me fail the class.(I'm also usually an all A student)