How do I stop thinking about my bf and worrying about the relationship ?

Hi, new here. Need some support. 

Things are great with my boyfriend (quick context- I'm 34, him 32, dated in early December, made it official early March). We see each other 2-3 times a week, have a healthy sex life, always laugh together, etc etc.

Yet, I am STILL so sad when I'm not with him.

Especially when he is working. And I don't mean his full-time job, I mean his two other side jobs.

He is in a band that plays at corporate events and weddings on one OR both weekend nights.

So when that happens we try our best to see each other on a week night.

I just get FOMO. Which is stupid. And not in a jealous way. Just in a "i want him to be thinking of me all the time" type of way. Which I know sounds ridiculous.

I have been trying to keep myself busy when I'm not working, but when I'm home, I'm sad. And I'm envious of the people he interacts with, like his streamer friends or people he plays his music for at his gigs.

I thought volunteering with an animal shelter and fostering a cat would help keep me preoccupied, but it doesnt. Its great and Ilove my foster cat, but its just not distracting enough.

How do I stop thinking about him so much??? He can tell he misses me and I’ll still feel sad and empty. I wish I wasnt like this. I need more hobbies and friends.