Can I blame laziness on senioritis?

Context: future applicant. I am graduating this semester, and received my first immunology test-grade back: B- ... which will most likely match my final grade. Is it ok to have this 1 W on my transcript? (this would put me at 9 credits)... 3 of these credits are already "sports" classes. the other 6 are humanities.

My sGPA is just under 3.5, and I'm a bit worried about the hit. Last semester I also only took 12 credits of humanities, but I don't want med schools thinking I literally can't science anymore. I have performed well in all my other semesters (>/=) 15 credits with a generous helping of science classes and an even grade trend.

Didn't make it clear, I'm thinking about withdrawing