I am sorry to hear that you had blood in your stool for the past couple of days, and that it has you worried. The differential diagnosis for why you may have blood in your stool is immense, and more then I will be able to go through with any depth in this forum. I would definitely recommend that you make an appointment with either your general practitioner, or a GI (gastrointestinal) physician to get a work-up. There are many questions that they will ask and will need to be answered to help narrow down what might be causing it. For instance the color of the stool can give a lot of information. If the stool is black and tarry, then chances are the bleed is in the upper GI tract, because when blood mixes with the acid of the stomach it turns that color. However if it is bright red streaks on an otherwise normal stool (i.e. normal color, and firmness, etc), it may be something like a bleeding
hemorrhoid. These can be worse if you are straining with stooling (for instance if you were constipated). Nonetheless it is never "normal" to have blood in your stool. It doesn't necessarily meant that there is anything really bad going on, but it is worth getting checked out to make sure. I hope this helps.