This sounds as a pancreatitis attack.
People, with only one episode of acute pancreatitis, can develop chronic form of pancreatitis overtime.
Abdominal pain due to this condition, is centered in the upper middle or upper left part of the abdomen, usually begining rapidly and is very severe one.
It is accompanied with symptoms like nausea, rapid heartbeat, swollen abdomen tender to touch, chills, weakness, feeling lightheaded or faint, headache, confusion, difficulty breathing.
The lower abdominal pains are most likely related to your constipation problem.
Anal bleeding is probably due to inner hemorrhoids, which can be manifested by passing large amounts of light red blood, or smaller amounts of blood covering the stool.
Inner hemorrhoids are related with production of excess mucus, that escapes the anal sphincter, gets onto the skin surrounding it on the outside, and dries there. This both dries out and irritates the area.
Also, an inner hemorrhoids can interfere with proper anus closure, leading to leakage of small amounts of stool, which also dries and irritates the surrounding skin.