Me and my friend/roommate both had blood in our stools? we ate out at a buffet this weekend and came back with diarrhea. although mine was worse.

Diarrhea: Diarrhea is defined as mild or severe. Mild diarrhea is less than 3 days duration and without dehydration or fever. Typically this will resolve on it own. Peptobismol good to take. If symptoms longer than 3 days or fever and dehydration then you should be seen.

E. coli: With limited information and suggested connection it is likely that you both experienced a self limited infectious type of colitis, out of many possible bacteria, E coli being notorious in causing specifically bloody diarrhea that may last few days. Would be careful about eating at the same buffet in the future.