"My family and fiancée have always been supportive of my choices" vs. "I started medical school wanting to do psych or path."
Focus on the YOU.
Think LONG and HARD about why you wanted to become a doctor, what interested you then, what interests you now, and what will keep you interested tomorrow until the day you DIE.
Personally, I'd leave someone and block out my family FIRST before I ever let them chose my career. But, my opinion may be biased as I am a non-trad pre-med and have worked in Finance for 10 years, been through several relationships, and learned that I am not my parents, which has set me on my current path as a non-trad pre-med.
At the end of the day, you must chose what you will be satisfied doing, DAY-IN AND DAY-OUT! This will be what you put you sweat and tears into. What you will wake up to... Can you imagine not wanting to get out of bed because you hate your job.
I am leaving Finance after being very successful, but cannot see myself doing this work for the next 30-40 years, let alone in 10 years.
You must first understand what you are comfortable being, doing, and whom you want to be surrounded by. I challenge you to ask yourself at the deepest level if your current situation is what you are TRULY comfortable in and what YOU envisioned your life would be like and that the path before you is what YOU hope it will be.
The biggest mistake people make (and I've had many before me and around me whom have shared their regrets after many years of success) is that they began their path because they wanted to make their parents, their father, their partner, etc. proud, but at the end of the day they finally realized that they made huge mistakes. Today, they are very successful, rich but total failures in their own eyes. These are doctors, lawyers, judges, politicians that I have been fortunate enough to have met and developed meaningful relationships with.
I began my own path to my current success as a means of survival, but now I realize after being told on many occasions by bosses, mentors and very close friends that no matter what I set my mind to, that I can and will be a success. But in those days, not too many years ago, I could only see the few steps before me that laid the path to surviving and being slightly better than I was at that moment.
You must see beyond surviving and see where you want to land and stay for a while. If not, you will only be working to survive your job until you reach retirement. Maybe you will be lucky enough to find success and find ways to make surviving less painful, but you will not be whom you dream to become.
Do you.
Ignore the rest.
Because one day, you will wake up old and full of regret.
Let that scare you into making the right decision for you now and for you tomorrow.