Hi Kitty,
I completely feel for what you're going through. Anxiety runs in my family as well and I've been dealing with it my whole life (I'm 35). But most of the time, I'm ok. Just sometimes, I have these episodes that last weeks or months. Right now I'm in the midst of one and it's all about my vision. I'm having terrible anxiety & I'm convinced something is very wrong with my eyes. I'm trying to shake it but it's been an enormous struggle. So my point is, I understand how you feel.
Now, you've been to many doctors & you've had all the tests done. You are healthy & nothing is wrong. Anxiety can absolutely make you feel like something physical is wrong when it's not. A few years ago, my sister felt she couldn't breathe, that something was wrong. She had heart tests, lung tests, you name it. Absolutely nothing wrong with her. Still, she had frequent episodes where she felt that she couldn't breathe. I actually witnessed her wheezing many times. It sounded like asthma but she didn't have asthma. So one day, she told herself very firmly that it was anxiety & anytime she felt an attack coming on, she told herself, "this isn't real, it's anxiety". She's much calmer than I am in general & doesn't usually have anxiety problems. So she was able to conquer her episodes just by talking herself through them. It went away & never returned. She is not sick & never was. This is how powerful anxiety can be. This is what it does to us.
I know this is easier said than done but you have to realize that all of your issues at the moment are a result of anxiety. You CAN breathe. You ARE ok. You're focused on your breathing the way I'm focused on my vision & we are making ourselves sick.
I'm here if you need me.