It's OK. I've seen people do school lots of different ways and come out fine. It's a little important to see if you can figure out what you love to do. Sometimes people pick going to med school because they don't know all of the thousands of other things that are available. So if you love science, maybe this is just a fluke and med school is OK. But if you hate science, then it does no harm to think about what subjects make you really happy to work on.
This advice might not apply to you, I'm trying to keep you from making the same mistake I made. I chose the wrong area to go into for the wrong reasons. I succeeded, but it was hard work and I hated it. I'm finally starting my second career now. I love it.
In the big picture, a D+ is not a big deal. Just don't make it a habit. Also, I think it's so much more important to find a college that fits you, then to get into a good college.
So don't worry, you're still a good person. You're fine. I teach college. I know.