relationship help?

So I've been with my boyfriend for almost a year and I couldn't be happier. There's one problem... I'm crazy jealous and insecure and he just moved to a new school where's his really close to all these other girls and it's driving me crazy. Since his moved, it's driven a wedge between us and it's all my fault. Everyday I cry because I'm convinced his cheating on me and finding someone new and better. Please help me so I don't ruin my relationship 😭