Calming anxiety?

I get worked up really easy. Over silly stuff sometimes, and I KNOW it's something I shouldn't really be getting all that upset about it, and I try to tell myself that, but nothing I do can bring me out of those emotions. It's like I have no control over myself what so ever. My boyfriend is going on a trip for a week with his friends which I'm ok with right now, but I know as soon as he's at the beach, I'll be over thinking like crazy. And I really don't want to feel that way for an entire week, or any more for that matter. It's hard to explain to him that I do trust him... I really do. But my brain gets to coming up with all these scenarios and I HATE it. What can I do to keep these thoughts out of my head? Or calm myself if I do get worked up? I seriously hate this.... I feel like something is wrong with me 😭