Hi welcome to Health care magic forum.
Thanks for calling H.C.M.F.
As you describe there was mild pain of abdomen, like cramps and gas pain. When you go to bath room there is tiny blood on the tissue paper.
The cause could be fissure in ano
, amoebiosis, or some infection of intestines. I advise you to consult a surgeon for diagnosis and treatment. you may need to have proctoscopy for confermation.
Wishing for a quick recovery.