Passing....barely

So I'm passing medical school. Barely, but still passing.
Its slightly baffling to me though. This last test....I definitely thought I'd done much better on and alas this was not the case.

My test average hovers just below passing by about 3 points. Thankfully, I'm passing everything else well so I'm passing my major class but I don't fully understand why I'm not passing.

I do study but I don't think its enough. As in I don't think I'm devoting enough time to it.
I'll be kicking the studying up this week. I'm going to try and put in more hours daily. I'm aiming for 4 tonight in addition to making flashcards. I'm really not sure what else to do.

Test on Tuesday.