Treating the test as a wake up call is nice and all but there's also a realistic component to this. Other posters' courses may have been structured such that a bad grade on one test is not the kiss of death but the OP's course may not have a grade breakdown like that.
For example, I once took a class where there was one midterm and one final. No homework, no quizzes, no labs, nothing. Just some assigned reading to do at your discretion. The deal was initially 50/50 between two tests. In that case, if I bombed the first test, then it's SOL. The prof eventually cut us some slack but that's just an example. If pulling a high grade looks unrealistic no matter how hard you study or requires the stars to align, the sunspots to line up, the moon to be full, the tides to be in, the tea party to raise taxes, AND you to do well from now until you hold your firstborn, then you gotta compute some p-values and see if the chances of you doing well is worth pursuing.