Intimacy insecurity and anxiety

When it comes to being intimate with someone I get really anxious and feel really uncomfortable. I can’t understand why I get like and lately I’ve noticed it’s effected my current life. Right now I am talking to a sweet and respectable guy but when I’m about to go see him I get so nervous and usually have a breakdown before. Do any of y’all have advice that would be helpful to combat this anxiety or any helpful tips I can do so that I don’t overthink?