You may have a case of Irritable bowel syndrome with constipation being a predominant form of bowel movements.
Stool covered with mucus is very characteristic for IBS.
The bright red blood indicates bleeding from lower sources of intestinal tract, like rectum or anus, and in your case it could be due to anal tear or fissure of anal wall lining or hemorrhoids (anal tear and hemorrhoids, both, are manifested because of constipation, straining and passing hard stools).
If you have all of these symptoms along with fever, it could be diverticulitis.
Mucus is, also, formed when there is an inflammation of the intestinal wall, but, then diarrhea, and not constipation is experienced.
Colon cancer must be always taken in consideration because of the vague symptoms it causes.
Personally, I think you are having IBS!
But, this must be evaluated by a gastrointestinal doctor!
And stop taking antibiotics, I don't see logic in that!
Best wishes!
Marija