Apparently I'm battling very stingy dragons, because despite being told that I'm absorbing their soul, I'm not actually granted any additional souls to use. This is obviously a bug, but are there any console commands to be used that manually add dragon souls to use before this issue gets fixed?

"player.modav dragonsouls - Gives number of dragon souls." - From http://elderscrolls.wikia.com/wiki/Console_Commands_(Skyrim) . Very useful website to find console commands.

Thanks! That's exactly what i was looking for. Hope this helps someone else out as well.