Hi, my 2 1/2 year old shepherd is acting really strange and I'm not sure what to do about it. He's been running around wildly and shaking himself off for a while now. I have checked him and he seems to be okay physically but I fear its something internal. I don't know if he ate something bad and that's what's bothering him or something else. I let him into my room so he could sleep besides me. He usually falls right to sleep but this time he couldn't get comfortable, moving constantly and biting his back legs. Any idea what could be wrong with him?