How do I stop being so scared to get back with an ex?

My ex and I have known eachother for 4 years we dated and broke up but kept in touch or hooking up here and there. But I never went full in as I am so terrified of getting hurt. I'm 26 and he's 28. This past weekend we hang out and it was the happiest I had ever been. To be honest i he is truly the only person I've ever truly loved. We decided to take things slow but the thought of being with him the getting hurt literally puts me in panic mode. I told him I couldn't do it anymore and that we should just let things be. He hasn't replied and knowing him, he won't. Do I need therapy because even relationships scare me.
How do I stop being so scared to get back with an ex?
Post Opinion