I am just starting my pre-nursing degree so while i don't have experience per say, i do know that it is still very early into the class, grades are volatile especially when tests come along because there aren't many points to offset the test in the first place. My advice? Suck it up, forget about what you got but remember the test style: Did she use a lot of questions from certain things like lectures, or the book, or labs? Make sure you don't study a day or two before, you should really be studying a bit each night to make sure you understand where you are currently. Never let yourself be left behind, find a study group if you need to. The best thing i do in classes to keep my grades up is i treat each coming assignment or test as a "How do i make this get me an A in the class?" Its more useful when you are around the 85-93% area, but otherwise just focus on maximizing each and every assignment/test you do. Don't fret, good luck!