It might be the hint of spring in the air. (We had thunderstorms and 50 degree temps the other day and a lot of the snow melted, yay!)
It might be that I've been at my job for 4 months and this is starting to feel "normal".
But the other 87.5% of feeling restless? I can't put my finger on it. I'm going to do some boring mindless cleaning today and see if the answer finds it's way out of my confused tangled snarl of a subconscious.