Organic Chemistry and Physics are clearly very difficult classes. They will both take a couple of hours each day of studying to achieve a high grade. Nevertheless, many students take those classes together and do fine. If you are at all good at math, physics wont be as hard as it seems first semester, but it may get hard by second semester.
Also, remember that most students have their worst pre-dent grades in these classes, lots of us got a couple of C's.
I think that if they aren't your best subjects and if you can split them up without holding yourself back in any way, that might be the thing to do.