Sink or swim? More like drown or doggie paddle.

Sensing that I was plagued by feelings of incompetence, inadequacy, and unprepardeness and believing myself totally unqualified and incapable of doing my job at the lab, my supervisor attempted to reassure me that everything would be fine, even after the fiasco that was my first solo shift. She said, "You know more than you think you do." Fortunately for me (and for the patients whose blood I analyzed), this actually proved true. I would go to sit at the microscope, petrified, as everything I once knew about how a lymphocyte differs from a monocyte fled my panicked brain. However, as I scanned the slides, I knew exactly what I was looking at. The clicks from the counting machine ticked off like rounds from a machine gun: seg seg mono lymph seg seg nRBC and Ooh! toxic neutrophil! Since that disastrous first night, my confidence has grown. I still question my results all the time, but in a productive way, rather than in an oh-my-God-I-inevitably-fail-at-life-in-every-manner way.
The danger in taking solace in the "knowing more than you think you do" adage comes when you start thinking you know more than you do. But how to tell into which category a situation falls? Perhaps the only way to find out is to dive in and see what happens. But what about when the water is teeming with flesh-eating piranha and infested with toxic fungi? When the stakes are high, as they almost always will be as a veterinarian, I historically err on the side of caution (not so much caution as intense self-doubt and reliance on help from others). I'm quickly discovering that this approach won't be feasible much longer; as a real live doctor, I'll essentially be pushed off a cliff into that treacherous water and will either be devoured by swarms of carnivorous little fish or doggie paddle and flounder about, keeping my head just above water, long enough to reach the shore alive. The biggest part of my mind (because it gets the most exercise) tells me that I'm not up to the challenges that await me in the latter years of vet school and in practice beyond, that I'm incapable of thinking on the fly, being solely responsible for preserving the life of living creatures, and working longer, harder, and smarter than I've ever had to before. The little portion of gray matter I reserve for optimism has to chime in and say, "Look what you did to get to this point. Look what you've done since that you've arrived. Weren't you thinking the same thing about the obstacles you've already conquered?"
In the past year, I've worked harder than I wanted to (and thought I was capable of), ventured miles outside my comfort zone (1500, from New Hampshire to Minnesota, to be precise), suffered through uncomfortable situations (some even more unpleasant than my currently 61 degree house), slept less than any human being should (I sleep so poorly and am so utterly exhausted at this point that when I wake up in the wee hours of the morning, I just start sobbing for the loss of sleep I know I'll never find again), and forced myself to exchange old habits (slovenliness, laziness, self-doubt, passiveness, and self-centeredness) for ones that will be requisite in tackling the myriad of daunting tasks that await me in the coming years.
I know more than I think I do. But is it enough? As I venture further into my chosen career path, most of what I encounter will be unknown, and I will be expected to not only face it, but understand it alone. I know more than I think I do, but can I do more than I know? I guess the only way to find out is to press on, to forge ahead, to find the strength, motivation, and sleep (the most doubtful of all) to keep swimming for the shore, even when challenges, doubts, and fears gnaw at my willpower like millions of tiny, needle-sharp piranha teeth sinking into my toes (oh wait, that's just the kittens going through a foot-biting phase).