My dog has been staring at me constantly since I came in at 4 o'clock

I thought maybe she needed a wee so we went for a run and a play in the park...
Perhaps she was peckish so she had a bit more dinner....
She was in pain (Staff blood in her somewhere so she never complains) but I've felt all over and she doesn't even look sideways at me...
ANY IDEAS??? She's just resting her head on my knee and staring at me :(