What have been the signs of ear infection in your little one?

LO has had a low-grade fever for almost 3 days now and has been really fussy, has been waking up frequently (sometimes with sharp cries), has runny nose and in the last 24 hours or so has started shaking his head back and forth (he has never done this before). At first I thought he had learned how to shake his head as a form of communication (he's 11 mo), but now I'm putting it all together and wondering if he has an ear infection.

I'm going to take him in to the ped tomorrow, but thought I'd ask how you've been able to tell.

Thanks bees!