Here's what you need to keep in mind: That you thought long and hard about this decision, and that you didn't make it lightly. You did the best you could. That's all anyone can ask of you.
The reason no one could tell you what to do was that it WAS your decision, completely. No matter how strongly anyone felt about this one way or the other, it was not their place to tell you which way to go.
Anon, now is where the hard work starts. Now you have to take care of you, make good decisions about your future, choose honest people to be in relationships with you, and move forward. You will naturally always think about this -- it just comes with the territory, and it should. Sometimes you will know you made the right decision; other times you will not be sure. That's natural.
Your parents do not hate you or think you are a slut. They also experienced a lot of emotions -- hurt, anger, disappointment -- but they would not have experienced all those emotions if they didn't love you and want the best for you. It waas unfortunate the way they found out, but in the big scheme of things, that's fairly minor.
Move forward now, Anon, and be kind to yourself. And if you think of it, keep us posted every once in a while on how you're doing, OK?