It is common for GPAs to drop a little when taking upper division classes. Obviously, the better you do in these courses the better, but it won't be that detrimental as you would only be going from a 3.8 to a 3.6-3.7 which is still at or above the GPA avg of most schools.
One thing you will need to figure out is why you dropped as you will be loaded down with nothing but upper division courses once in dschool. If you are having troubles keeping up with the material, then you will need to figure out how to stay on top of it because you will be given so much more info in dschool.
Don't stress..... a little drop shouldn't keep you from getting in to dschool.