I think if you want to continue with Science you should aim for something in the industry field and not pure research. If you think the stress of a medical career will be too much for you, the stress of research science (at least in life sciences) will be all too similar. Unless you like competing for money all the time, 16 hour days and no weekends, thousands of deadlines etc. Like, you need to be passionate about the field to exist in pure research science.
Industry gives you money, you can work <15 hours a day (\o/) and you get weekends.
Do what Hobbitle says - find something that interests you in undergrad and worry about the details of the matter later. And who cares if you don't know what major you want to do now? I didn't decide on a major until the end of my second year and I almost didn't pick MIIM. Now I devote literally 98% of my time to it and I'm horrendously in love with it. I'm sure you will find something that interests you if you just keep exploring. Second year is a better indicator. Just go through the handbook and find things that sound interesting - within reason, if you're missing a prereq and you have a good grade, you can usually get a waiver from the university to go into a major (eg if two subjects were required for the third year subjects but you only did one, and you can make a case for yourself deciding to change your path, and you've done similar sorts of subjects which you would have because you do Science). Also, if you don't know what you're doing in your degree right now definitely avoid breadth in second year if you can and fill up your time with more Science subs to get a better overview of what interests you.
Don't worry about what is 'academically impressive' - when you said that I was quite concerned. Nothing in your undergrad is academically impressive, it's a black hole of 3 years in which you are meant to ~find yourself.