If your goal is medical school, your first concern should be earning strong grades. You can expect a slight decline in sophomore year so start strong and end with a Nike swoop if that very likely sophomore slump occurs.
You can make up for deficits in volunteerism, clinical experience and the like over the summers and even after graduation but bad grades will follow you around like dog sh1t on your shoe.
Consider that many faculty will expect you to put in 2-3 hours of homework for every hour of classroom time. Typical college load for a pre-med is 17 hours of classroom per week (with some of that being labs which are often 1 credit but 2-3 hours). So figure 20 hours engaged in class/lab and another 40-60 hours of prep, reading, writing, studying. In light of that time commitment, how much working can you afford to do in your 168 hours per week? (Keep in mind that you need to sleep, bathe, eat, maybe exercise, too and take care of your mental and spiritual health).
tl;dr: Don't over commit and tank your GPA. You can save money but pay more in the end for GPA repair.