You should probably see a doctor before you get too freaked out. Like, clearly blood isn't a good sign, but before you start saying good bye to everyone because of cancer, go to a doctor and make sure it's not just a weird infection or something.
You should go checked by a doctor as soon as possible, it could be internal bleeding, I forgot what it's called but it can turned into stomach cancer but then again it could be nothing serious and your intestines are irritated and it will go away in a few days. I won't keep going don't want to freak you out. Just stay positive and don't worry i'm sure you're fine.
well at least it doesn't appear to be fatal if it's been going on that long but seriously you need to go to a doctor, it's probably only getting worse over time. You might need surgery.