I have anxiety/panic attacks with a lot of physical symptoms. I experience all the symptoms you mentioned, maybe some others too: heart racing, (at least thinking I have) difficulty breathing, feeling like I might pass out, shaking, confusion, blurry vision, red face, numbness in hands, cold sweat, stomach problems. I know these are terrifying. So your problems could definitely be anxiety/panic. I told my doctor I thought it was weird I had so many symptoms so frequently (I'd say almost every day I have at least a few symptoms at various times of day, usually at night), but he said that's just the anxiety. I just happen to have a LOT of physical symptoms. I know when I first started feeling all these things, I thought I was dying, I thought I must be having a heart attack, but I saw a doctor, had an EKG, blood tests, etc, and have nothing physically wrong with me. Maybe if you haven't had that done, you could, just to be sure? It helps me, knowing, hey, I am fine, I am not dying, this is the anxiety right now. I think it helps a little bit with coping. Hope this helps!