Dog might hae a stomach ache. What to do!?

Question
My dog is a rat terrier he's usually very active and happy, today he doesn't even want to get up and walk.  He hasn't barked since the early morning.  We gave him his own food and won't even eat that when usually he wants to eat everything. he stands up and tries to strectch but he can't he lays back down. I've looked around to see if he vomit but he hasn't.  Could it be just a stomach ache? or something more serious? What should I do?  

Answer
He could have a stomach ache or he could have pulled a muscle in his lower back. That is a common cause of pain and inappetence in dogs.

You could give him until Monday morning to see if he feels better since you are sure he didn't eat something bad. Dogs have good days and bad ones too, but not as often as we do!

You might want to give him a tums or two, but make sure they are just plain tums. If his tummy is upset that could help.

If they don't then get him in to see the vet Monday morning. If he is really lethargic tomorrow and won't drink water you might have to find a vet open tomorrow as that is more serious. You don't want him to get dehydrated so make sure he is drinking water. Withholding his food is recommended if he is vomiting.

Please let me know how he does.