I have bloody diarrhea with white stringy stuff mixed in. what is it? what do I have?

today I went to hockey practice farting quite a bit, I felt no need to poop, as I was putting my gear on it felt like I had a small gas pocket coming on. when I got on the ice and started to move around everything sorta loosened up and I really needed to go bad. I knew it was diarrhea from the feeling. I had to hold it for an hour and fifteen minutes then I finally went. it was diarrhea. I didn't really examine it but it looked like normal diarrhea to me. later I got home and I felt the need to go again. and again it was more diarrhea. this time it was more liquidy. looked fairly normal in color. and just 3 hours later I felt the need to go again. I went and there was less diarrhea but it was like a maroon color (brown poop mixed with blood). also there was some white stringy stuff all around it. not sure what that is. I've never seen anything like it before. please help me out. I'm 14,male if u need to know. thanks