Why am I pooping blood, doctors? Nurses? EMT? ?

Hi, the past month when I've been going poo I've been pooping blood. First it wasn't a lot just a little on the wipe. Now it's A LOT! I mean I wiped three times and there was a good amount. Then I looked in the toilet and there was at least 4 tablespoons of blood in the toilet. It's a pretty bright dark brown blood if that makes since? I've been feeling really tired lately, I've been getting these bruises on my inner arms that I have NO idea where they come from, I have 3 right now next to each other, and they've been getting darker as the day goes on. My mom has crones(sp?) disease. I don't know if that has anything to do with this. Also my stomach has been cramping really bad, not like my lower stomach, the whole thing hurts! Almost like labor. I was just wondering if maybe anyone could give me a clue as to what's been going on. Thank you.