Relationship Anxiety Is Ruining My Happiness, Even Though Nothing Is Wrong

I don't know if anyone else feels this way, but relationship anxiety is exhausting. I'm in a healthy relationship with someone who treats me well, communicates openly, and has never given me a reason to doubt them. Yet somehow, my brain is constantly looking for problems that don't exist. If they take longer than usual to reply, I wonder if something has changed. If they seem a little quieter one day, I convince myself they're losing interest. Rationally, I know none of these thoughts make sense, but that doesn't stop them from showing up. The hardest part is that the anxiety isn't coming from my partner—it's coming from me. I spend so much time worrying about losing the relationship that I struggle to fully enjoy it while I have it. Sometimes I feel guilty because I'm creating stress out of something that should make me happy. I want to trust more, overthink less, and stop treating every small change like a warning sign. Deep down, I know love isn't about having constant reassurance; it's about feeling secure enough to believe someone cares about you even when everything isn't perfect. I'm curious if anyone has actually overcome relationship anxiety. Not just managed it for a few days, but genuinely reached a point where they stopped overanalyzing every message, every mood, and every interaction. If you have, what helped you get there? Because I'm tired of feeling like the biggest threat to my relationship is my own mind.