I hope you know that getting into medical school is just one part of the long uphill battle of becoming a surgeon. If you're already so anxious, nervous, and depressed now, how will you manage the hours you have to put in for med school studies? Relax and don't overthink it. Just do your best and see what happens. Talk to friends and family for support. One person I always go to if I need someone to talk to is my brother; he's been a huge help for me with regards to the application cycle and what to expect in med school. Besides, one bad semester is not going to kill your chances if you show that you are committed to getting into med school. You also need to prioritise what you should spend more time on; your ECs or school? There's always time for more ECs, but having to do another undergrad or redo failed courses would be a pain.
Trust me man, I've been there before. It's tough to deal with. But here's what you really need to do: take this one thing at a time. In other words, there are so many tests you're going to take down the road that determine your becoming a surgeon. Like the surgical boards exams or step 1 or your clinical evals. If you looked at any of those now they'd seem completely impossible to you, just like some college-level maths would when you were in high school. But by focusing too much on the long-term, you can psyche yourself out and actually screw up what's right in front of you -- THAT's NOT GOOD!
Look at it this way (and not to put down any med school): I see an ad from a neurosurgeon who went to Ross for med school. If he can make it into one of the most competitive surgical specialties after going to one of the lowest ranked med schools out there, ANYTHING CAN HAPPEN.
Just get into med school. Take it from there. You're right, if you freak out this much in med school it will be super-tough for you. But use this time to figure out a way to manage that stress. Seriously, talk to someone about it, devise better study strategies, maybe make a schedule you can stick to and promise yourself not to "overstudy" and exceed it.
You really need balance and it's good that you've recognized you don't have any right now. Now is a really good time to figure it out. And, when you are at an interview, and an adcom asks you about something you've struggled with, you can bring this up (you know, don't couch it exactly in terms of "I have no life and study all the time and it made me depressed," but maybe something about test-taking anxiety and time management and how you dealt with that stress and it made you a better person, blah blah, the stuff they like to hear).
In short: stop worrying about being a surgeon. Stop worrying about getting into medical school. Just do well where you are, and you won't close any doors.
I'm going through this now, and I found that two things help:
1) Getting organized about how/when to study and do assignments.
2) Finding one, just one, creative outlet that fits within my budget that I can work on a bit every week.
In more detail:
1) I got this schedule and, in pencil, I plan what I will work on during the day. For example, I may put Spanish class from 1-2 pm and so on. Within it I also plan time to clean, eat/cook, transportation time, and when I take breaks for the hobby. If I don't get to do what I planned, I erase what I wrote for the hour and write in what I did. (Helps if I studied Bio for 2 hours rather than Bio then Spanish, also helps show when I procrastinated/had other things to do. Helped keep track of total hours studying per week and has increased me from 15-20 hours being crazy/scared to 30-40 hours studying with time for activities).
A list of what's required for the week is attached, and if I get nervous, I add another list that divides assignments by days. (Had to do that just a few minutes ago for this week's plan.)
Print it blank since you don't always know what you'll be doing at the planned time: http://www.nlight.com/Success/Study/PDFs/weekSched.pdf
2) I've recently gotten back into sewing (I'm female xD) and that's helped me with the creative thing. It's cheap and I don't feel like I'm wasting time like I do with watching TV/playing video games/shopping. Its fun to have to focus on a hobby that requires attention to detail because I forget about everything else. And its nice to see I can accomplish things in a way that has nothing to do with grades, so I don't feel like I'm wasting effort like the days I get nervous studying.
If you happen to be religious, see if there's some form of religious writing/teaching that you can refer to if you're having a bad day. That's actually helped me the most.
Do you actually need to study that hard to pull the grades you do, or are you working excessively and worrying about things that don't come to fruition? I just wonder whether you might be developing a legit anxiety problem over this, for which you might want to see a counselor to help steer you back towards more realistic perspectives and towards gaining some balance in your life.
If you really do need to work that hard - consider that medical school is going to be just as difficult, if not moreso. Is this really what you want? Have you had real-life experiences to confirm that you want to be a surgeon, and not something else? Consider what you're going to have to sacrifice to make that dream a reality, and ask yourself why it's your dream in the first place. What I thought in high school was my dream completely changed through my undergrad career, and it took me years - through undergrad and after - to really confirm that I wanted to be a doctor.
Don't worry about whether you're "fitting in enough EC's" - do what you're passionate about, and do things that are meaningful and effective; no more, no less.
You need to have balance in your life for yourself and your mental health, and also (I hate to say this to you, but..) so that you can show adcoms that you have maturity and perspective, and more to your personality than just 100% Premed, All the Time.