Trust Issues

So im with my very first boyfriend and im his first girlfriend. We met in may and we’re super in love. He’s the sweetest person ever and I couldn’t ask for better. But I tend to overthink and get jealous and insecure very easily. For example if he has female friends or follows other girls on social media. I know he wouldn’t cheat or do anything like that to me, but I cant help but get super jealous and insecure, and I cant help but to think “what if?” Ive had pretty bad anxiety and overthinking issues for a long time, so maybe thats why im like this. But this sometimes makes him think that I don’t trust him even though I trust him with my life. I need help with knowing how to explain these feelings to him and make him believe that I do trust him.