Dr appt today

Well today I saw the lung dr or as I refer to him as Dr Doom because of his underwhelming attitude. The good news is my lung function test improved.  It was 33% a month ago and now it is 45%.  I told him I was exercising and walking 960 ft.  He did not seem impressed.  I asked him for a pul rehab script he gave it to me and that was that.
He said I may improved more before I level off but I will not be the same as I was.  Contrary to what he told my son last month.  He said I should get back to where I was but now it is another story even after showing improvement.
The not so good news is I am still on oxygen.  He checked my o2 and it read 93%, I asked if I can get off oxygen and he said no because my levels will probably drop below 90 without it.  He did not check if they would drop he just assumed.  I dare not question the almighty one about his job. He does not like me questioning anything he says.  I was thinking of another dr but I am afraid they are pretty much the same.  I would like to go to cleveland clinic but that is so far away, about an hour drive.
I think I need a day to rethink my relationship with him.