I Recently Quit Smoking After 25 Years And For Some

I recently quit smoking after 25 years and for some strange reason my health has seem to have declined in a way. I was diagnosed at the ER with a bronchial respiratory infection in March of this year and prescribed prednisone as well as a steroid inhaler. In the past few months I have experienced the smokers flu and some chest pains as well as body aches shortness of breath at times and headaches. I also feel very confused and disoriented and sluggish most of the time. I don't know what is going on please help.