Is there something wrong with my two ten week old kittens?

I received two ten week old kittens from a lady last week who had given them flea, ear mite and deworm treatments. Last week they also went into the vet for their first distemper vaccinations and a check up. Everything was good on them. Starting today one of the kittens won't touch their food and rarely will drink the water maybe for sips here and there but rarely. It slept most the day but when its up it does play just had it had the last couple days. I'm wondering if this is normal for kittens. Also the food I'm feeding them is the same the lady used for them and he had been eating it just fine. The other kitten has a bout of diarhea it doesn't look like he is in pain and he eats fine drinks fine also plays good. The diarhea is not like liquidy it is like melted chocolate then after a lil inch long poop comes out as well. I guess I'm just wondering if this is all normal. I've had cats but never kittens. Thanks for any information u can give me!