Hello & welcome, I am Dr. B, a licensed veterinarian and I would like to help you with today. I do apologize that your question was not answered before. Different experts come online at various times; I just came online, read about your wee one’s situation, and wanted to help.
Again I do apologize that my colleagues could not aid you sooner, but can you tell me:
How much blood was in the diarrhea? Was it just a bit or was it all bloody/mucusy?
Has your lad been vaccinated?
What do you think he could have eaten? Any bones, toxins, toys, plants, etc?
Can he keep water down?
Are his gums pink or pale/white? Moist or sticky?
If you press on his belly, does he have any discomfort, tenderness, or tensing?