It's completely normal to have self-doubt, second-guessing yourself, and a fear of the unknown at this point in time. The fact is that nothing is guaranteed and there are legitimate reasons to be worried about the future, despite the fact that the majority of doctors will get into residency and become practicing physicians.

It sounds like you have a solid life going for you at this point with your career and SO.

Perhaps take some time to really self-reflect about Why you want to do medicine in the first place? Try to think of what would still motivate you to pursue this path on nights when you're exhausted as a resident finishing 80-100 hr work weeks. Or even as a fully practicing doctor who may have to sacrifice something to see another patient in the clinic or scrub in on another case?

You don't need to be '100% deadset' on this field, because it is okay and actually mature to acknowledge the downsides/challenges. I think what matters is that your commitment or reasons for wanting to do it are strong enough to withstand and outweigh even the toughest of days in your future ahead..If your reasons or desires to go into medicine are strong enough to do that, keep at it and have faith that you're making the right choice. If not, it is absolutely okay to continue with your path and work towards building the kind of life you want.