ETA: I think this is correct:
I worked on this last night but couldn't figure it out for the life of me. This is the setup in my bathroom. It's an older house so there is no ground. I'm trying to figure out where the juice is coming into to the circuit from the fusebox, either at the switch or the light/outlet. I used my multimeter and got the following results:
switch turned off:
> continuity between the black and white wire on the switch
> no continuity between the black and white on the light/outlet
> continuity between the switch white wire and all other wires
which would lead me to believe that the juice is coming in at the light/outlet, and going back out on the black wire on the switch.
My aim is to add an outlet somewhere on the circuit between the switch and the light, and I'm trying to figure out how to do this.