3months Post Breakups

Its almost 3 months since my Ex and I broke up. He dumped me because he already gave up on us and he didn't want us to be together anymore. I couldn't get him off my mind, even though I already started going to the gym or doing other side hobbies I still always think about him. I wish I could stop. But i still stalk his social medias and kept overthinking if he already has a new girl which makes me anxious even more.