In particular this part of your post bothers me: “The experience haunts me to this day..”
No - This shouldn’t be the case. You did nothing wrong. While there is no magic wand to “fix” how you feel - and esp low probability that an online post from a stranger would do anything but please consider the following strategies:
1. Try to understand shame. What is it and Why it is there? (evolutionary reasons) It might be liberating.
2. Know quite simply that the past doesn’t exist. Except In our heads.
3. Take inspiration: http://www.bbc.com/news/magazine-37735368
4. Try to research into revenge porn - what happened to you is very common; in some parts of the world with serious consequences for women - understanding that you are not alone (or special) might be oddly liberating.
5. Talk to someone. Maybe even a pro.
Just some strategies that are available to you - hope you heal soon. (I am sure you are already trying to recover - Your message just stuck a cord and I wanted to offer advice)