You should call your doctor because you have may internal hemmorhoids which you may need suppositories to clear them up. You also may have a fissure. There are other possibilities that can cause blood in the stool such as Chrone's, colitis, and other inflammitory bowel diseases, but i'm pretty sure that most of them are accompanied by bloody diarreah and more severe symptoms. You should call your doc for peace of mind, but it sounds like hemmorhoids.
I had the same, which was rather worrying because my mother was going through a gastrectomy for stomach cancer. Turned out to be hemoroids and painless to sort out. 2 were banded, 1 injected.
what a relief!