And this is my first semeter of college for which i heard that once you screw up your GPA it can be diificult to bring it back up. What should I do? How bad does a W look on a transcript?
Not true at all. "Rough starts" in college are more common than you might believe. You still have many semesters remaining during which you can adjust your study strategies and receive higher grades. There are plenty of posters on this forum who will share their "abysmal" freshman year GPA's alongside medical school acceptances. You really have nothing to worry about at this point other than learning from your mistakes and attacking your upcoming semesters with greater rigor.
As for whether or not you should drop the class, a W is generally something that you want to avoid, but having a few interspersed throughout your application will not be the end-all of your medical school prospects. I personally would only drop a class, however, if I were going to either fail it or receive a D-grade and there were nothing that I could do about it. I don't believe that dropping a class to negate a C-grade is worth the additional scrutiny/explaining that will be necessitated by the appearance of a W. In your case, I'd say stay in the lab and see what you can do to pull that grade up. If you end up with the C-, well, it's only one credit, and if you never receive another grade that is lower than a B in your life, you'll hardly notice its effects on your GPA in a year or two.
