I have had that same exact problem. My doctor prescribed me some anusol suppositories. The prescription said insert 1 (one) every 12 hours as needed and I only inserted one and it did the job. This was March 22,2002 and my bleeding has stop. I thank the Lord for that.
Sounds like hemoroids or a fissure, but you should check with your doctor to be sure it's not more serious. For hemoroids try witchhazel compresses and preparation H. Make sure not to get constipated by eating plenty of fiber, drinking lots of water, and getting some exercize like walking every day.