I ended up ahead $28 on Saturday, but got my butt handed to me (down $58) on Sunday. I guess I shouldn't move to higher limits ($1/$2) when I'm not feeling well, although I don't recall any bad plays that I made. I've downloaded my hand history and will be analyzing it tonight to see where I went wrong.
I suspect that it was just a run of bad cards, and the few times I got good cards, they never hit (e.g. A♥K♥ lost to pocket deuces), or worse, ran into trouble (e.g., A♠Q♠ ran into K♠K♥ and A♦K♣).