22 m here. Last December, while having a bowel movement, blood poured out of my anus and stained the bowl, also had a lot of blood on the toilet paper. Went to the doc, had a per rectum which didn't find anything, waited for a colonoscopy and had it done in February 2018. It came out clear besides one small benign polyp which was extracted. Anyway, after having a clear colonoscopy I stopped paying attention to my stools and toilet paper and just kept living life. However today, I accidentally looked in the bowl when it was flushing and thought that I saw some blood on the paper. So I sat down, wiped again, and there was quite a lot of blood on the toilet paper, and it kept bleeding for about 5 minutes, if I strained harder, the more blood would come out. It was bright red and painless bleeding, clearly lower in my GI tract. Now I'm quite stressed and considering three possibilities:
1) Colorectal cancer/anal cancer was missed on the colonoscopy
2) New cancer formed between my colonoscopy and today.
3) An internal hemorrhoid formed between my colonoscopy and today.
Any insight please?