You have a lot of insight in to what a career in medicine involves!
I absolutely agree with you regarding the amount of memorisation, I found medical school a huge exercise in memorisation and regurgitating the appropriate facts in exams, not really gainign a deep scientific understanding (there really isn't the time!), and there wasn't really much on the curriculum that was conceptually difficult to grasp. Anatomy was always my weak spot because I found it the most tedious to memorise. In my experience the complexity occurs in later years, in terms of applying all those facts you have learned to clinical practice, because there often isn't a right/wrong answer - you will often find one consultant manages a condition somewhat differently to another, and both with their own good reasons - deciding what is right for that particular patient in that circumstance is where the deeper thought and clinical judgement comes in. I felt that's when things got much more interesting.
You are also absolutely right about a career in surgery, the operating side of it is only one part of the job, you will spend at least as much time doing non-operating work, fo example ward rounds reviewing your patients pre- and post- op and looking after emergency admissions who will not require surgery, and there are a lot of outpatient clinics. There's lots of tough conversations to have in surgery, e.g. making the decision with a patient and family whether to operate or provide palliative care. Remember though, if you did stick with medicine, you would be trained to do this- it does not come naturally to most people.
On the other hand, medicine can also open doors into other careers, for example pharmaceutical reserach, which may be more aligned to your interests. Remember also that there are options to do a year out of medicine to do an intercalated BSc (I did mine between 3rd and 4th year which is quite common), so during your medical school journey you could incorporate some more scientific training.
It's a really hard decision to make, because once you leave medicine, it's very difficult to get back in if you ever regret the decision. On the other hand, I personally would probably not stick with something that I am thoroughly unhappy with - after all the rest of a career is a very long time! A medical degree could however open other doors for you down a non-traditional career route, for example a research career, so it's worth exploring those potential options before you make your decision. I do feel bad that your parents pushed you so hard down the medicine route. It may well come from a good place - from the outside, medicine looks like a very secure career (people are always going to need a doctor regardless of the economic conditions etc!), it comes with a good salary compared to many other graduate jobs, and if they are not from a medical background, they may not understand the emotional toll that it can place on you. Have you discussed your feelings about medicine with them?