Hey,
I sort of felt the same, I already did quite a few medical subjects in depth, and although the workload is high, it is not really
difficult; I also did a minor in computing science and math, so I know what difficult and challenging means, since math is not really my strong point. I really had to work hard to even understand it!
With medicine, it was usually pretty logical, but I know I really want to become a doctor, since I really like knowing it all and stuff, but whenever I don't find it challenging enough, I find something very difficult for me (like graduate level maths....)
It does change though, as you get further you go much more in depth and you discover certain systems in the human body that are very fascinating and can be quite tricky to grasp. Plus, you have to know a lot to understand how it all works.
And that's the thing, you have to start at the basics... And basics in general aren't really that difficult

And it's not really 5 years, it it? You'll get your clinical years at a certain point.
So the question is, do you want to become a doctor? Have you shadowed any doctors? Or have you done a nursing internship? That would probably help you make a well informed decision.
I would recommend finishing your year anyway, then do an internship, and if you
feel medicine is not for you, then quit; there's no point in doing something you don't like or doesn't fit you.
But then don't regret it afterwards! Don't let your mother tell you it's a shame or whatever; mothers know you the way they want, not necessarily the way you are (however nice they can be!!).
You know what's best for you
good luck!