Ok, @Vikinggirl, it could had been something he ate in the house, maybe paper towel or something..you're right, he eats anything his mouth touches, I'll have to be more careful!
@deserskybulldogs, he is eating TOTW puppy dry food Pacific stream, I will also follow your advise. I'll keep you posted. Thanks!
@cowsmom, Frank is doing great, the whole weekend was fine, we took him to the mountains ( we live in a concrete city, no green areas around) and he was so happy and playful, thanks God, it might have been that he ate something that made him vomit