as one side of your tube is having block possibility of natural fertility
will decrease to some extent though not completely,
so as your doctor told you can try for 2 to 3 months by that time possibly you can conceive, if egg releases on the right side it can pass through the tube easily and chances of conception is there, if releases on left side some problem may occur for fertility.
so if we take it into consideration that eggs may usually release alternatively, you have to conceive in 2 to 3 months period, if not you better to go for artificial reproductive procedure as told by your doctor,
usually old tubal blocks will not get releaved with medications.