I recently have been waking up like I'm suffocating

[LoveLilBit]

I was born with a heart arrhythmia which I have not felt for long periods of time. The last 3 months I have woken up feeling like I am suffocating. I have also felt I was losing oxygen or heart was stopping while I was in a conversation & had to get outside which I had fell down in the process of standing w/ my front door open. I also felt I couldn't breathe & would pass away while I was dreaming, this is the first time about 2 months ago. The only changes I've made are exercising more, I also recently started eating a lot (which I don't eat much. But I have always had a fast metabolism) I do take mess for anxiety but I've never felt this way before except maybe once or twice in my past but a long time ago which still was nothing compared to this