medical studies are so tough as we all know.you need to do conceptual studies.if your basic concepts of pharmacology is clear then you need not worry to much.it is not possible for a human being to learn everything which is written in books .you can do 1 thing,write important & basic drugs name,their uses in various conditions,their classification ,its mechanism ,their interaction on a paper & learn these drugs name daily 1 hour in the morning.concentrate in class when the teacher gives lecture on drugs & their uses..you are in 3 year means you clear 2 year of mbbs.in my view,you have a capacity to become a good pharmacologist in future.1 year timing is good enough to study pharmacology.
best of luck.