Shelly,
The only way for you to have been exposed to rabies is if the cat was rabid and you had been exposed to their saliva. Even if the cat was rabid and introduced saliva into a wound of the dog the dog would not be infectious until the virus reached the brain/salivary tissue which takes days to weeks. As Reks said you should talk to your doctor if you have any concern but waiting until you return home is not likely to be any great risk.