10 week old puppy has diarrhea. There was also a tiny, very small amount of what i think was blood. Helpppp?

Hi, I just got a new 10 week old pomeranian puppy on friday (2 days ago). He has been completely fine except for tonight when he started having liquid diarrhea. His poos have been quite soft but not liquidy. I did start giving him new treats today so hopefully this is the cause of the diarrhea, but i also saw a very small amount of blood in this diarrhea. Also, a small piece of ceramic came out in his diarrhea. :S Not too sure where he found that cause we cleaned everrrrrywhere before he came. Anyways, has this ever happened to you or do you know if I should be seriously worried here? Any idea what could be happening? Thank you.. 10 points to best answer!