Hi Dave,

All the best to you in your excellent career choice.  Given your newness, I can certainly see why you may be uncomfortable at times.  While a lot of BA skills require a "learn as you go" approach, to address your immediate concern, I suggest the following.  Since you have difficulty (understandably) with info overload, your penchant for diagramming and table is certainly a step in the right direction.  You might also consider mind maps that help you crystallize your understanding while showing rela'ships among topics.  Last, a mark of a good BA is to always consider the forest, while being able to dive into the trees.  Any outlines you can create - showing broader topics with subsidiary sub-topics will be of great help too.

All the Best!