How To Work on Self-Improvement, and Ignore Those Who Try To Put You Down?

I’ve always been a level headed girl. I have also been known as a “good girl” a majority of my life. Not too long ago, I made some bad decisions. I began hanging out with the wrong types of people, and doing things that I knew were wrong, but it made me feel good to finally be noticed for more than just a well-behaved pretty girl. It felt good to hear people talk about me, even if it wasn’t good things they were talking about. I lost many friends along the way, and didn’t realize that until recently.. I have some good friends in my life right now, who have really helped me through some of the toughest times in life. There was an event that happened recently, which i’d prefer to leave off of the internet, but long story short it was a huge mistake. It was then when I had a “breakthrough” so to speak.. I realized that the reason i’d been feeling so empty inside is because i’m not by any means happy with the way people view me now. I hate that people think i’m a slut who just whores around with guys and parties all the time, because that’s not me at all. My close friends see it, but no one in my school seems to get it. People talk about me on a regular basis, and I always hear about it. People even go so far as to post terrible things about me online.. It’s getting to be really hard on me. There are people who act like my friend when I know they really just talk about me as soon as I can no longer hear them.. I’ve tried to accept it, and just be the bigger person and move on with life, but their childish ways really bring me down ):
I have really been trying to become a better person lately, and i have been succeeding with help from my friends. It hasn’t been long enough for people to notice my efforts.. I’ve had some people tell me that they really respect me for it, but I can tell they’re just being fake. This is all for me though. I’m not changing to please anyone but myself.. So I guess what my question comes down to, is what are some good ways to focus on my goal, and not let people hinder the progress i’ve made? I don’t want to go back to my old ways, at all. But people are really making it harder for me. Some days I just want to give up and go back to being my old self. Because I feel like it’s not going to change anything, anyway. I feel like no matter what I do, I will still get crap from people for it.. I don’t know I guess i’m just looking for some friendly advice.