Is sick and at the vets.

.. Not sure what is wrong with him. Out of the blue yesterday afternoon he started coughing/hacking. He would have several episodes in a row. He didn't seem out of breath or in distress but uncomfortable and once awhile he was panting like he was hot. He is eating/drinking/elimating ok. He was still very active, like wagging his tail and getting excited when I would talk to him, however he would cough if he got too excited. He doesn't seem sick, other than the coughing. I dont think its kennel cough. He is never around other dogs other than my own, none of the others are sick. The only other dogs around us are my moms right across the street, they are never around each other and hes not sick, and the neighbor dog, one house away and that poor thing lives outside on a chain.
SO Im worried that it may be something really serious,

he is 8 years old, gained quite a bit of weight because of the phenobarbital he is on for is seizures but otherwise has been an extremely heatlhy dog.
The thing that is bothering me the most is that I cant shake this feeling that its his time to go.

. Has soon as I heard him coughing yesterday I have felt this way. It was a long night last night. Anyways, if you all could say a prayer for him, I greatly appreciate it.
I will update as soon as I hear something from the vets.
Terri..