I felt that way when I was in the 40's for awhile. My suggestion to you (if you haven't already) is to get the process of getting on the transplant list going. The reason I say this is because the first round of testing is really long and demanding. It's a couple of days worth of stuff and it takes all day. That way these doctors are familiar with you, you have all the preliminary testing out of the way. So if your lung functions drop down even farther, they can monitor you and get you on the list quicker if need be. Trust me, these tests were difficult for me when my functions were in the 40's. I can't imagine having to go through them if they were lower. I was fortunate enough to get my lung functions higher by going to pulmonary rehab and due to Orkambi. However, I am still listed but my name isn't active. Meaning I'm too healthy for a transplant but I'm in the system. I do however have to repeat some of these transplant tests yearly now so they can monitor my progress. Something else if you haven't done already is to get onto disability. It sucks, but the way I look at it is CF is now my full time job. You need to take care of yourself first before you do anything else. I had to stop working but I was able to rest my body and get things back under control on my time. Also when you get on disability, they have some work from home programs that you can do. So that's something you might be interested in doing as well. Or find a job where you can work from home. The main thing is that you take care of yourself first.
