Stuck with nowhere to turn.

[tiaheartswaffles]

So I'm in the nave and I've gotten all three ingredients for Agrippa's tonic. I have 5 out of the 6 pieces of orb, but I did have all six at one point. I can't load an earlier save, because I'll lose my ingredients, and the game won't let me load farther back than this afternoon. I know I can't get ambushed by the monsters in the Chancel until I have all six pieces of orb, but I've gone back to look for the pieces in all the areas, and can't find it. So, tell me, am I screwed or is there something I can do?