Bleeding During Bowel Movements, Nausea, Appetite Loss. Taking Flagyl. Abdominal Pain. Is It Food Poisoning?

I am still bleeding when I go the bathroom with or without stool since last Saturday I had constipation that caused feeling of vomiting until I stupidly took a dosage of peptobismo and there after had diarehea cramps fever for 24 hrs and after all stool was discharged blood bright leeked out every 10 minutes on Saturday, 5 to 6 times on Monday, and began lessening daily, but discomfort, nauseous, loss of appetite has persisted up to know. I have been taking flagyl 500 mg starting on Monday prescribed by my doctor's associate but I see no improvement. I went in to see the doctor this past Monday because of the continuous blood and about a pain in have on my lower left side of my abdomen which was extremely tender when I was examined on Monday? Do you have any idea what can be wrong is it food poisoning or could this be the after math of a recent colonoscopy I had the end of September. I have felt bloated and have been constipated since ( all so there has on occasions there has been blood in the stool after pushing. There has been no fever only on last Saturday. I feeling week and even the smell of food is nauseating. It's like being pregnant again. (I am in menopause since I was 49)