I have been having rectal bleeding for sometime now and sometimes it is mixed with the stool and a lot of the time it is not mixed, now i am 31 female and also i have lost some weight i been to the doctor and they said that i did not have hemorrhoids, now what i want to know could this be more serious then i think and i also want to know if someone takes a lot of Tylenol can that cause the rectal bleed it is not constant it comes and goes when should i see the doctor about this