I haven't 'liked' someone in for a long time

You know that feeling you get in your stomach when you see that girl who just makes you stop and think wow. When you know all you want is to be with them. Arguably one of the best feelings in the world right? yeah I forget what that's like and I haven't felt it in 3 years. I really want to again.

Now I've recently come to the conclusion that perhaps the reason for this is; the last person that made me feel this way, I really liked but it was unrequited. And that was pretty much the last time I'd felt that about anyone. I wonder if perhaps subconsciously I'm not letting myself catch feelings for someone again because I'm scared of getting hurt?

Sidenote, I still know this girl and I'm still friends with her and find her very attractive and I love her personality but I still don't even have that very specific feeling for her

Side-sidenote, this is just a theory I came up with. If anyone has any advice/thoughts on that theory or they're own theory as to why I seem incapable of feeling like this both are equally appreciated, thanks