Good Morning and welcome! I am Dr. Loretta, a licensed veterinarian and I am happy to answer your question.
I am so sorry to hear about your tiny sweet Shilo! This breed is very sensitive and I believe that he is suffering from a digestive disturbance. This could be due to something odd that he may have ingested or some form of stress that you may not even be aware of. The treatment for this is as follows:
Fast Shilo for 12-24 hrs which he is doing himself to allow the digestive tract to calm down and heal.
Give him Pepcid AC or Famotidine at 0.5 mg per pound every 8 hrs. That can be purchased over the counter at the pharmacy.
Give only small amounts of water during the fast or ice cubes
After the fast, feed Shiloh rice and boiled chicken (2/1)
If he is feeling better, wean him back to his regular diet. This blood you see is caused by the soft or hard stool irritating the very sensitive rectal mucosa which, in turn, causes small blood vessels to break and bleed. This is not serious and will resolve once the disturbance resolves. I know the blood appears scary but it is not serious for your sweet Shiloh.
If this does not resolve, have your vet examine him to be sure we have not missed something for your sweet little guy.
Does that make sense to you?
Please let me know if you have ANY other questions. My goal is to give you 100% satisfaction and if you are not yet satisfied, please REPLY so I can clarify for you.
Sincerely, ***** *****