everybody studies differently. I think one of the biggest mistakes you can make is comparing the amount of time you study to other people... it'll end up freaking you out if you study less than they do/way more than they do. You just have to study till you feel comfortable with the material.
I study A LOT more in med school than I did in undergrad, but I am not very good at memorizing. (a great skill to have in med school, btw). Its not totally horrible though. You just have to be efficient and organized. If you can get into med school, you can get through it, don't worry bout it 🙂
ps: as an aside for all you pre-meds, one of the best study tactics of all time is to quiz one another. I never studied with other people in undergrad, but have found that studying on my own and then quizzing with a friend the day before my test is incredibly effective. It helps to fill in details you may have overlooked (or intentionally avoided b/c you thought they were ridiculously unimportant, in my case usually!), plus you always remember facts you are asked to recall on the spot.