What causes Puppy has diarhea and lost weight?

I am from Romania. Yesterday my seven week puppy westie teriere was brought from Hungaria with a car where there werw many other puppies. We took him home. He was starving so we gave him some dry food..those little marble cookeys..dog food for jouniors. He vomited them. When he got home he pooped many times. the poo was normal. he sleeped very much. At night he started making some sounds..2 or three times. They sounded like hickups.Then he vomited again. This morning he had diareea. i think his tummy hurts because he cryed a little. He has his parvo is done and a deparazitation. how cat i take his temperature?? what should i do to stop the diareea an the vomitig..what is wron with him. please answer because i am realli worried for the little felow :((