Does anyone else have huge swings in the way the COPD affects them daily?

I do not know if I am just in denial. I never know what my copd is going to do from minute to minute . In a typical day I can go from being comfortable to being driven to my knees due to lack of air in a matter of hours. I dont know which way it will be or what changes it so fast. Eating even a small meal makes it so I struggle and cant lay down to sleep as I cant catch my breath. It can change so fast without a visible reason I am afraid to go out. I am thinking there must be another part to this puzzle the VA doctors hav'nt discovered yet. Is it (hate the word) Normal to have huge changes several times a day with no obvious causes? One time I can walk to the bathroom comfortable on 2 lpm and they next trip I go to my knees on 4 lpm. I am sure anxiety has something to do with this as I can never figure in advance what will work. This isn't new I was diagnosed in 2010. I do have an inactive spinal stimulator in my spine and have been blaming that, but the VA doc swore the electrode between t-7/9 could'nt affect my breathing. my cat scan says mild hyperinflation but my breathing test shows end stage. Have probably bored everyone with too much info but anyone else with huge swings would be very informative and maybe let me relax and accept what is going on, instead of always trying to find the real reason.