Bleeding Ulcer?!?!?!?

what are the symptoms of a ulcer in a dog?!?!?!?
my dog ate aspirin, about 3 hours ago, and puked yellow stuff after he ate the aspirin, but no blood in it. and he looks well no signs of distress.
will he be okay?? he is a 2 1/2 year chihuahua 8-10lbs.
he at 6 AT THE MOST, so he probably ate 3 to 5 maybe.
i cant call the vet or anything cause its 12 amBleeding Ulcer?!?!?!?
Call the vet NOW. There are 24hr emergency clinics if your vet is not available. The normal dose of aspirin for a dog that size is 1/4 tablet. The problem will not be bleeding from the stomach. It will be kidney damage or kidney failure. So your pet may appear well now but could still suffer kidney failure. If you pet receives immediate treatment this most likely can be prevented.
See vet. asap.
Usually there are emergency numbers for vets. Usually when you get a checkup or something like that, there is a list of numbers like Sunday numbers or an Emergency number. Try calling 411 or something like that.
He's probably fine. Let him have some milk, or water to drink.