NO. Your chances are not over.
A tip: Do not get too consumed over your grades. Do the best you can, but do NOT flip out because of a "sub 4.0" semester or quarter. IMO, if you hold your gpa above 3.7, you'll be fine.
Get involved in things you are interested in over the course of four years of college. Great applicants to medical school are those who are well-rounded individuals. The funny part when I say this is that I believe many people start to think, "well, what can I do to make me well-rounded?"
Do stuff that you like. I have a close friend to loves to breakdance. I have a friend who is a marathon runner. One person loves to do woodworking. One is a water polo player. One loves to play golf. Make yourself interesting, and enjoy life. Often times, these "fun" things are great for you because it helps you get away from school, but also it actually strengthens your application. (Yeah, surprise surprise.)
That being said, don't just start breakdancing, running marathons, play polo, or play golf just because I said I have med school colleagues who do those activities. Do what YOU like to do. It's like this, when people say what do you like to do, and you say (insert activity here), followed by the typical, "but I hardly have time for it anymore." MAKE TIME FOR THAT ACTIVITY. THAT'S WHERE YOU START.
Look. Just for once try to think about what if you were a medical school admissions committee member.
ARE YOU SERIOUSLY GOING TO RANK A GPA, RANK AN MCAT, THEN DRAW A LINE AND EVERYONE ABOVE THIS LINE WILL BE ACCEPTED?
No. You're not. After a certain point, it's about what you bring to the table. a GPA and MCAT really brings very LITTLE to the actual bargaining table. It's just used as an initial screen for schools. Each school is different.
When I was interviewing, I had people when we had to go around the room to share something interesting about ourselves, just literally SUCKED at saying anything interesting. One guy literally said, "well, I'm kinda boring." REALLY, WOW.
Don't become that person.
Grades matter up to a certain threshold, but afterwards, its who you are, what interesting things you do, that makes you a good candidate.
Addendum: I think this might summarize my point-Being involved in something interesting that means a lot to you outside of school, can MAKE YOU as a applicant. But grades really cannot make you, they can only BREAK YOU. Therefore, after above 3.7, don't bother being neurotic about it. Just do the best you can, and focus on the rest.
I applied with a sub 3.5 GPA and I'm happy with where I am now.