I just cant believe this is happening to me

This is like the most worse, embarrasing thing that can ever happen.
I was having some bleeding upon BM last year about this time. I went to the Gasto and he said probably fissure. He gave me a cream to use. I went back and had a colonscopy done last June. He said I had a small hemorrhoid. Nothing else on my colonscopy.
Since then I have had these symptoms
light anal itching, some light blood off and on, burning/aching after a BM, some purple engorged vein looking things around my anus (I have been doing self exams-who knew I was a contortionist)
The pain isnt bad, its just the burning/aching. If I use preperation H it burns at first but the pain killer stuff helps. I also used some desitin this morning which helped for a while.
Also I had my gyno annual last November and he did a digital rectal and didnt feel anything.
My question is could the doc have missed anal cancer from the colonoscopy?