Getting divorced made me sit down and think about similar things. For one, I put a lot of my happiness/identity in being a father and a husband (partially as a cultural thing). For two, I had been living for other people and doing what I was "supposed to do" for so many years that I had to sit down and really think about what I valued in life. DO NOT put your joy in anything that can be taken from you, including your career. You can't control what happens in your life. You can only control your own actions.
I can't tell you what the answer is, but I think I can tell you what the answer is not. Putting your "happiness" (whatever that means) in wealth, or the approval of others, or prestige, or being at the top of a hierarchy- none of those things will make you happy in the end. There will always be someone who is more "successful" than you.
For me? My faith has a bit to do with it, but I've decided to focus on A) living with absolute dedication to my craft and B) focusing on nurturing good relationships.
With my academic performance, I could match into an easier specialty than Family Medicine that would also pay me more. Having said that, if I don't go work as a primary care physician where I grew up, nobody else will. Those people are counting on me. And the more I know, the better I can take care of them- there aren't any specialists out there. It's just family docs and a general surgeon. Of course working 36 hour shifts isn't worth it for the money. But it's worth it to go serve those people who loved me from the time I was a child.
All that being said- again, I can't tell you the answer. But I would advise you to find some sort of noble pursuit you can devote your life to and strive to use that for the benefit of other people. I think that will lead you to peace. Whether it's medicine or not.
And all of that to say- it really doesn't matter that you're getting Bs in biochem. Stop worrying about making as much money as possible and start worrying about how you're going to serve the world. And about the perfectionism thing- it's literally impossible and it's holding you back from achieving your potential. Go read the essay "A Way of Life" by Osler. If you live like that, the outcome will take care of itself.
Stop worrying about the outcome. Worry about the process. Be utterly disciplined (hence
Rock Lee is my avatar haha). And then whatever the grade is, you can hold your head high and know you did a noble thing. Oh, and it's OK to have friends/a partner/whatever too. Medicine doesn't have to be your life.