Blood in stool but suddenly turned red to dark blackish?

Blood bad in stool. Any amount of bleeding in stool, be it bright red, maroon or black demands prompt and thorough evaluation. Many of the causes will not just go away by themselves and may be life threatening and or life shortening. Go for immediate evaluation.
See a doctor. This needs to be evaluated by a physician to determine the cause of the blood loss.
See your doctor asap. as blood in the stool is never normal Black blood usually means it is coming from the stomach and has changed color due stomach acid and enzymes affecting the blood. If a lot of blood or black or you are dizzy or weak go to ER.

Related Questions

Intermittent red blood in stool since I turned 14. I am now more than 19 years old. Never had any related testing. No other symptms. Is it concerning?

Yes. From what your described, you may have internal hemorrhoids and loss of blood could lead to anemia. It would be prudent to see a doctor for an evaluation and treatment. Read more...