Can you give me some advice on how to stop worrying about my relationship?

So I’ve met this guy who’s now my boyfriend since Feb this year.
We have a great relationship and even though we haven’t been together that long and our relationship is still not rock solid I have never been this happy in my entire life. He is the kind of person I’ve been longing to meet for years. And now that I’ve found him I’m death frightened of losing him.

I’ve made the mistake of ruining previous relationships by worrying too much and beeing to needy so I don’t want to ruin this too.

I know I have nothing to worry about, but I keep getting these scenarios in my head, such as ‘what if he suddenly stops loving me’? what if he meets someone else?

Can someone help? What is a good way to stop being anxiuous?
I guess I’m anxious because he means so much to me, and I am afraid of losing him.