Hello.
Thank you for your query at DoctorSpring.com.

I understand that blood in stools can be quite a distressing symptom but let me assure you that you cannot have colon cancer. Colon cancer is a rare cause of blood in stools and there are other benign causes which are much more common such as hemorrhoids, colonic infections etc.

Looking up your symptoms in the internet most often causes unnecessary anxiety and is best avoided.

Colon cancer is commonly seen in those above 50 years old patientof age. You being only 21, there is no risk of such a thing.
Also, cancer of the colon does not present this way. There is usually a long history of abnormal bowel movements, such as alternating diarrhea and constipation with or without blood in stools. There might be weight loss too. A family history of colon cancer may also be present.
In the absence of all these, there is nothing to suggest cancer in your case.

You are most likely to have hemorrhoids, especially if you have a history of either chronic constipation or a recent bout of severe diarrhea.
Hemorrhoids can be confirmed by a per rectal examination by your doctor. Please stop worrying about cancer and consult your GP for the examination.
Meanwhile, make sure you have a good fluid intake, along with a fiber rich diet.

I hope this was helpful. Feel free to ask queries.

Regards.