tell him what is going on...all the mundane, boring details! Instead of saying "not much" say that you just got slammed with a huge project at work, or that your mom keeps picking fights with you, or that your neighbors got a dog that barks till all hours of the night...if he senses that you are being open with the little details like that, then he'll be more likely to believe you when you say that nothing much is new (romantically, i assume?).