Hello! Thank you for the query. If your symptoms do persist for some time now and you do not associated it with food poisoning you need some diagnostics for sure. Blood in stool should always be diagnosed as it can be caused by inflammatory intestines disease (Crohn`s disease, ulcerative colitis), large intestine polyps, colon cancer (unlikely at your age), hemorrhoids, sometimes due to IBS. Transparent clots are probably nothing more than mucus which can be present with all mentioned diseases. So if your blood is red (not black- black blood usually comes from peptic ulcer), you should have colonoscopy performed. Abdominal ultrasound, full blood work should be also performed. Hope this will help. Regards.