Ex bf still continues his smear campaign after a year. I can help feeling bad. What should I do?

Was at dinner with a friend of mine. Two girls came into the restaurant who were friends of my ex who kept pointing at me (they whispered ‘that’s her, she is the crazy one..etc’). They even sat close to us (maybe to hear what we were saying) and then left. It’s been a year but it still hurts every time. A few people I have met have then without any reason removed me from social media/avoided saying hi to me after- I’m sure it has something to do with him. It really is not pleasant. Specially seeing as he seems happy now with someone new (seems like he is wining) and made me look like I’m the crazy one.