When my [23F] boyfriend [24M] is not around, I start doubting everything

My boyfriend (24M) and I (23F) have been in a relationship for almost a year. When we are not together, I get anxious and insecure about our relationship. I start having thoughts that he might not love me or that I’m not good enough. It’s not caused by the fact that we spend alone time (I’m fine with that), it’s just that when he’s out of my sight it’s like his love for me is out of sight too. But when I do see him, I feel secure and confident and I don’t have those thoughts. Any advice on how to deal with this?