Severe anxiety with breathing trouble. Scared and expecting third baby!

I have been suffering from severe anxiety for 3 years now. I hate it. I would consider it health anxiety I suppose. I ALWAYS think something deadly is happening to me. If someone passesaway from a certain condition, I automatically assume I have it. I literally feel it. I have had mri's done as well as several tests run on my heart and all of this has been fine. My anxiety triples whenever I am pregnant. The newest syptom happening to me are the pauses in breath that I keep having. During the day while I am wide awake, I feel my breathing stop for a few seconds. Then I get really light headed and I struggle to breath. I feel the need to see a pulminary doctor because I fear my symptoms are deadly. I do not know how I ended up this way. I live every single day in fear that today will be the day I die because I can't make myself believe that anxiety causes all of these symptoms. My family has heard me say that something is wrong for so many years and ofcourse all docs say everything is fine..So everyone refuses to believe me. I am tired of feeling like I am crazy and I don't know what else to do. Could anxiety causes breathing pauses? What are your syptoms and how do you cope? I am begging for any advice.

Tash, I do the same thing and I am not pregnant plus I am a 72
year old man, not making fun of you just explaining, When I am
really stressed I do this without thinking, sometimes I am grunt
breathing that's what I call it, its like I am expecting to get hit
and I am swelling up without realizing it, then sometimes I just
am not breathing properly, the cause! "Sever Anxiety". you will
be ok its common for a Pregnant Woman to experience shallow
breathing, use to keep a brown paper bag to hold over my Daughters nose and mouth, she would actually pass out from
lack of oxygen. "God Bless you and all your Children". Peace
Larry ***