Is my toy poodle eating normally?

I just adopted a pure bred toy poodle a couple days ago. Since i've brought him home, he hardly eats. I am feeding him twice a day, and each time he's only eaten 10-15 little kibble bites. I am using the same dog food the breeders used and am softening it with a little warm water. I bring him over to his dish and for a few times, he'll eat and then after the 10-15 pieces, he runs away and i can't get him to come back. He seems to be straining to poop also. I take him out every couple of hours and he almost always goes pee, but only poops a little tiny bit. It doesn't seem to be too hard, and its not diarrhea. It took him about 5 minutes and it wasnt any bigger than a dime size. I am just wondering if this is normal or if something is wrong with him!! By the way, he is 8 weeks old and weighs 2.05 lbs.