Why is my dog throwing up in the morning?

have a 8 week old male Hound/German Shepard mix, as of three nights ago he started waking up dry heaving and sounding like he is trying to cough something up. This only happens when he wakes up from sleeping almost all night; sometimes he makes it till 3:00 am and sometimes he makes it to 5:00. After he gets up and gets moving this does not happen, he acts normal in everyway besides this, he is an energetic , playful puppy. after he gets over his..'morning sickness'

Thanks for your answers

You may have to call a vet to get a clear answer. I've been searching the net for you and so far, the only thing I've found similar is this...it's a reply to a person whose puppy has the dry heaves - the answer is from a vet:

Your dog is attempting to vomit. With or without any food coming up, the indication is the same: she has a stomach ache. Persisting for about a week suggests the problem is more than just a transient batch of food that disagreed with her system. She may have parasites, an infection, food allergy, gastritis, or other ailment.

You should feed her mild dog food, such as lamb and rice, or chicken and pasta. Do not add any spices or other foods. You can add onion or garlic for flavor. If she continues to dry heave or regurgitate, then her doctor should see her. A veterinarian can test for allergies, infections and other problems.

I heard that when dogs try to throw up but can't that means their really sick. If I were you I'd take him to the vet quickly.