Medfag here, and like everyone else has said;
If its bright pink AND IT HURT to shit, then its just a hemorrhoid, use vaseline on the area and your butthole for the next few days, you're not shitting when you're suppose to, when u feel a shit coming on, your body has hydrated the area for you to shit out a poo.
If its bright pink AND DIDNT HURT, then its a bit more serious, and means there is a broken vessel in your intestine - only old people get this.
If you shit bright red blood for longer than 2 weeks then you gotta see someone, but i think you're pissing the same hemorrhoid off.
If you are genuinely scared, eat fibrous breakfast every morning and use loads of Vaseline on your asshole, should fix it. Cancer is rare, the internet will tell you its cancer, stop being a pussy. The doctor might be able to prescribe your some hydrocortisone (steroid cream)