That sounds a little bit like when I was in college (MD/PhD program right now), except that I needed to work while in college to help out my family. I definitely felt the pressure to achieve, especially after a less-than-stellar first year of college and switching career plans from education to medicine (taking 20 credits of pre-med a semester). Through a lot of trial and error, I figured out that doing what I love and making time for family and friends (since it was college, after all) helped me to stay focused and less stressed out, even while doing a lot of extracurriculars and research...
I found that stress happened when I felt obligated to participate in activities that were not really my passion and merely took up time from my day.
As for medical school, provided you make decent grades and get a good MCAT score, schools usually look for meaning in your extracurricular activities and commitment to one/a few, rather than how long your resume is. College grades (and even the first two years of medical school) don't really determine residency placement, unless you failed something badly without any mitigating circumstances--more how the clinical years go and what the letters of recommendation of someone in your field say about your potential in the field.
Feel free to send a message if you want to talk more about it...
