Thanks for the additional information.
Given his status as an intact male, I would be concerned that the bloody urine may be associated with an infection in his prostate or within the urinary bladder itself. He is a bit young for the formation of cystic calculi (stones within the urinary bladder), but this is another possibility.
The blood in the stool is associated with colitis
, an inflammation within the large bowel. Colitis can occur for several reasons but in Winston's case it is most likely due to stress and developed secondary to the urinary tract issue.
Thank you for checking for the spots. These pinpoint areas of bruising are called petecchia and would indicate that Winston had a bleeding disorder, such as from rat poison. I'm very glad to hear that all looks well in that regard.
As long as Winston is able to urinate and he otherwise seems ok, you don't need to rush him in to the ER vet. For tonight, I'd recommend trying to encourage him to drink lots of water in order to flush out his urinary tract. Withhold food overnight to allow his digestive tract to settle down and for breakfast offer him a bland diet of boiled chicken
or boiled hamburger and white rice in a ratio of 1/3 meat to 2/3 rice.
Have your vet take a look at him tomorrow. He will most likely check Winston's temperature to assess for fever, palpate his prostate via rectal exam, and perform a urinalysis and fecal exam.
Based upon these findings, he can get Winston the appropriate medications.
If Winston seems painful, is straining but cannot urinate, begins vomiting, or the bleeding worsens, he should be evaluated on an emergency basis.