Insecure in myself

Okay so, I'm with the man I want to marry and most of the time I love myself but lately I am just so insecure in myself. I over think everything including text messages etc. from my be especially. I know it's my anxiety getting the best of me but I just want to be better and have more confidence so that me and my man can be stronger. Can anyone help me or give tips on how to gain more confidence?