Gagging dog.

Last night, my dog was in his crate for bed, when I heard him gag for the first time. I got him out, and he immediately wanted outside to ravenously eat grass. He stayed up all night, wanting to go out and eat grass, and gagged intermittently - like he was trying to throw up. He never did.

He's pretty restless, but the gagging isn't persistent - only every once in awhile. He's eating normally and drinking a little more water than usual. I'm trying to think of anything he could've eaten - and the only thing that comes to mind is that he had a bully stick for the first time 2 days ago. However, the gagging didn't start until last night. He's not lethargic and eating and drinking, so I didn't want to take him to the vet and get charged an expensive amount for this to just be something mild.

He's also gulping intermittently and seems to be breathing a little heavier. Something is bothering him - I just don't know if something could be lodged or if his stomach is bothering him. Is there anything I can do at home to find out more?

He's still eating grass like crazy - which is not typical. He's 3 years old, 75lbs and has been in great health until now. He's had his heartworm medication. When I first rescued him 3 years ago, he had kennel cough from the shelter I got him from. I don't think this is the same thing - he's not coughing persistently - more of a gag, and the grass eating indicates to me that he's either sick to his stomach, or trying to get something unlodged from his throat. Other than that, he's still barking at our neighbors through the fence, and alert - just more restless than usual and not sleeping very well. Any ideas of what this could be? (Sorry for the novel!)

Thanks Dr. Marie, I appreciate it. Is there any reason he's eating so much grass? He normally never does this. He's not sleeping at all because he wants outside constantly - I'm worried about not sleeping myself tonight! :) Under any circumstances can I give him hydrogen peroxide to see if he will throw up whatever may be bothering him?