Today when I used the bathroom, I noticed a slight red tint in the toilet water. My feces did not appear to be discolored or anything, but when I flushed the toilet, I saw that the red tint was indeed blood (it swirled around when the toilet flushed).
The blood could have been in my urine, but I urinate on a fairly regular basis and I haven't noticed anything wrong with it in the past.
More information: I am not an active person, and my appetite is probably below average in size. For a while, I have defecating usually once every two days, which I know is not normal. Because of my obsession with school, I am often very stressed, and I don't get enough sleep (I usually go to bed between 11:00 and 12:00 and get up at 6:30). I sometimes have stomachaches at night, but in the past I chalked most of them up to stress. I occasionally take a dramamine pill to stop the stomachaches if I can't sleep. I'm a boy, so it isn't my period or anything. I'm sixteen years old.