Dittos Panda Bear...
The reading load can be tremendous, but isn't always necessary. Almost every professor likes to feel important and will "require" a lot from you. This becomes interesting when you have multiple courses competing for your time. It is up to you to be the material filter. For most medical school classes, lecture transcripts, handouts, and review books are enough to do well. Big texts can usually be used for reference, but can be avoided for daily reading.
For some classes, you will have to read everything, and your 2nd years can advise you there. Just keep in mind that when you are covered up, it is likely that everyone is just as overwhelmed as you. Grading in medical school is usually relative, so often the goal it simply to keep up with the pack.
Good Luck!