Am I overthinking?

Before me & my SO actually started dating we had that talking stage, this one time he went to hang out with one of his ex's & went to the park. He told me they didn't kiss just a hug when they said bye. After me & him had turned like a year or so she msged him on Facebook asking him if he had called her & he told her off kinda, he told her he didn't call her that her number has been blocked ever since they last talked. That he doesn't want a friendship or anything from her that he's okay with me & that I'm all he needs. & just a bunch of stuff. Right now my anxiety got bad again & i feel really insecure. I feel so insecure about her specially, although he told me so many times how he was never able to love her, that he didn't know exactly why he couldn't if she was really nice to him. & it's like he has been able to actually grow feelings for his other ex's except her yet she's the one that gets to me the most & idk if it's because of how she looked for him & what not. I hate it, i hate how I always imagine them hanging out again behind my back this time. Today he last msged me at 3, & usually that never happens, if we stop texting early is by 7-8 or so. Our weekends is when we see each other & maybe cause of my anxiety i can't think straight so i can't help but think & imagine the worst... i hate this, i hate my anxiety.