To answer the OP's question, yes, I started to lose steam as well. There did not seem to be a logical order in which to tackle the quests and the story seemed a bit fuzzy to me. And yes, the inventory drives me a little batty as well.

All that said, I'm still very much enjoying the game and the only thing I can suggest is to just keep exploring and keep saving your games. Not just the quick saves but name your saves so you can recognize them later. I found I needed to go back to a save point in Lucella and lose about an hour of play once I finally got the gist of what was going on. It's not that I HAD to; I wanted to.