Carcinophobia's really got me?

Ever since I read an article on brain tumors and was convinced my headaches were coming from one, I've been in a lot of anxiety regarding cancer. This has happened before, but it's been a little while, and there were several months where I wasn't worried about it at all. Never even occurred to me. Now I'm worrying myself half to death with this. My new fear is cancer of the small intestine. Asinine, right? I know, but I can't shake it. I've been having a lot of abdominal aches and cramps since Friday, but especially today. They're sort of everywhere - upper left just below my ribs, upper right in the same place, lower right, lower left, sometimes central. I don't think I've had pain this consistently before, so it's scaring me a bit. Also, before today I did have nausea when I ate. It seems to have subsided a bit. My bowel movements are sometimes weird - usually I go once a day, but there are days when I go 5 times! I don't notice blood, no black/tarry stools, and I don't think there's mucus or pus, but I am going more often. Sometimes one bowel movement after another! I don't think my IBS has ever caused this before, and the pain I'd always have with IBS was lower central abdominal and sometimes upper left and right, but never in all those other places. I've also been getting backaches and joint and muscle pain. The pain, again, usually begins after I eat, and is dull and collicky. I've been pretty tired too, though I can still exercise well somehow. No weight loss, and my appetite is still good. I know that's a lot of info, so I guess my question is, does this check out with small bowel cancer? If not, what would be expected if I did have it?