Breathing issues related to my ulcer ?

I have had a stomach ulcer since October last year and had a contraception implant in April. I am currently taking omeprozole but for a few weeks I am feeling breathless as if I can't get enough oxygen and constantly tired, this had got worse in the past week. I went back to my doctor 2/3 weeks ago and was told it was probably related to my ulcer as I am also coughing, my doctor did not check me over and I am now worried about how I feel, I am waking in the night struggling with my breathing and scared to go back to sleep. Is this a usual thing with a stomach ulcer? And will it ever get better