Very scared and not sleeping much.

HI new to the forum from SC .My doctor just told me I have mild copd. I dont fully understand the numbers but my pretest FEV 1 is 80 and my pretest FEV 1/FVC % is 82.8.I dont know if those numbers are good or bad.Are post test numbers more important? A doctor and some of the nurses at my doctors office have tried to raise my confidence by telling me that my symtoms are mild and that my allergies are the bigger problem and that if I get those control I will feel much better.Thursday I was having trouble breathing (hard to say how much of it was anxiety ) and I was given a steroid shot that made me feel better than I have for 3 weeks .I felt normal again.What I cant a stop thinking about is how much longer will I be normal.My breathing seems good now but is it just a matter of time before that changes for the worse? My brother who is 10 years older was diagnosed with mild copd 9 years ago and he is doing fine (He smokes some to this day .I am a non smoker ) and he is telling me not to be afraid but I feel like my life has changed forever for the worse.