Blood/Red along with Bowel Movement?

I'm a 14 year old male, and well, I just took basically a poop, and along with it came something i perceived as blood. The poop itself was a little darker than normal, but not black. The water was discolored and was a light pinkish color. When I wiped, it was bright red for the most part. I did have a bit of discomfort while...um...excreting my bowel movement, but I didn't notice anything extremely abnormal. Also, this has been happening more than usual as of late. Usually, it would happen occasionally, and only be a little bit, but now it's been happening more often. could this be caused by a small change in my dietary habit? I've started eating a small amount of salad every day lately, and it's just a spring mix that has some cabbage (I think that's what it is, it's a deep-reddish leaf). So yeah, if you can make anything out of this, please tell me because I'm kind of worried.