I Have Been Treated For Many Years As Having Allergy

i have been treated for many years as having allergy issues -- now I have been tested and confirmed that I have asthma -- I was just given Breo used it for two days and had chocking mucus that I was not sure if I needed a rescue inhaler --- could not lay down because I was so chocking .... stop taking the med and it took almost 3 days before I felt I was back to the throat clearing and cough level of before ... now they want me to use QVAR2 is that going to cause the same misery !!! those two days were beyond frustrating !
I am 66 years old