Hello. I have had this terrible new anxiety where I have been scared I'm gonna stop breathing. 

I have had trouble breathing since September and have seen so many doctors and a cardiologist and neurologist. All clear. I went to the allergist recently and am not allergic to anything but told me a thing called "fake allergies" meaning changes in temperature, humidity, air pressure, can trigger feelings of fake allergies. (I only had trouble with breathing and dizziness so I am. It convinced it's fake allergies)

He gave me a nasal spray that takes a week to work but it made me so sick with runny and closed nose, and congestion in my throat and my chest that I had like laboroured breathing at times. 

I called out of work to go to urgent care and they told me my lungs are fine and that my oxygen levels were fine too and that it was just my sinuses and gave me antibiotics. But I still feel like my breathing is so hard to do sometimes and it scares me and last night I only got 3 hours sleep because laying down made me feel a heaviness in my chest and my breathing was short. (I was clearing my throat most of the day before I laid down to sleep)

Should I stop the nasal spray? I don't know what to do and my first thought when waking up is "you can't breathe" repeated over and over and over again and it's worse at work too! I am so behind in my work because I'm too focused on being scared that I will stop breathing. :( 

Anyone have this breathing problem? Is it anxiety