I don’t think it’s necessary to reconsider already. If you can use this last semester of HS and then summer to “get your mind right” and focus, you can totally hit the ground running in the fall and be good-to-go. But, like others have already said, without discipline and good study habits there’s absolutely no way you’ll make it to/through medical school. I’ve seen first-hand what’s required to make the cut, and it’s nothing short of strong determination.
My recommendation, take a couple of the required pre-med classes in the fall to get an idea rather quickly whether or not it’s the path for you. Chem 1 and Bio 1 will let you know rather soon if you’re really into it.
Good luck!