I'm having bloody stools, diarrhea, bright red blood from anus in underwear, and sometimes cramps

Best to get checked: I would suggest making an appt with your doctor soon. This could be symptoms of an infection from something you ate or drank (like salmonella for example). It could be a condition called inflammatory bowel disease (like Crohn's). If you develop fever or outright abdominal pain, go to urgent care or the ER. If not, see your doctor soon.