AS can affect the ribs where they attach to the spine and also where they attach to the sternum (breastbone). If you have inflammation or fusion in these areas, it can affect your ability to expand your ribcage to take a deep breath.
Pain meds can cause mood changes, which could possibly account for your feeling of doom. It could also be from depression. Definitely discuss this with your doctor.
Ginny - 57 year old female
Dx with USpA in March 2013; changed to AS in July 2015
Iritis and Scleritis
unicompartmental knee replacement June 2014
MTX, Humira, Cyclobenzaprine, plus Celebrex as needed
Supplements: Folic Acid, Vitamin A, Vitamin D, Calcium, Fish Oil, Melatonin, Culturelle probiotic