Every once in a while friends don't agree with our lives when we try and change them for something more positive. There are friends that like us a certain way, and when we change (even when it's for the better), they are uncomfortable with that.
That seems to be what has happened to this person that wrote to Dear Abby. She made mistakes, then met a guy and wanted to change for the better. Her friends said she "shouldn't have to change for a guy." Well, true, you shouldn't have to change the person you are to get someone else to want to be with you. But if you meet someone that inspires you to improve? That's different than trying to change just to be in their life.
It's not uncommon for friends to be uncomfortable with a change in your behavior, even when that change is positive. If your pals can't instantly support you, give them some time. However, if they continually want you to go back to your old self, maybe you need to move on to friends who support you. Friends should bring out the best in you, not wish you to go back to your worst.