Awaiting tests & diagnosis, oxygen saturation question, very distressed

Almost 47, mom of 2 young kids, smoked on and off since 18, longest quit 3 years, but on and off all the time the last 15 years really.

Only 8 stone, usually fit but sports injury put me out of action. 3 bouts of pleuritic lung over many years, the last, in Nov should have been followed with an xray but wasn't thanks to covid. After that I quit for six months but got my heart broken & went back on cigs with a vengeance.... got awful 'cold' constant running nose, hacking, crackly cough, felt bad, (down/ tired), really desperate cough but felt like I wasn't clearing phlegm, blowing one nostril easily 30 times a day, breathiness, a 'heavy' breathless feeling in lungs when walking fast even though still able to walk fast just fine.... presumed it would resolve in days once i quit again.... but it didn't

Quickly realised something is different this time. Went to doc, he instantly told me this is serious, and possibly emphysema. Stethescope told him there are crackles in my lungs when breathing - BUT that finger test showed oxygen saturation of 99% so he said couldn't be emphysema, said maybe fibrosis.

Walked out the door, googled fibrosis of lungs... that one is fast and terminal.... but a doc on a Stop Smoking forum has since told me i can't have pulmonary fibrosis with saturation of 99% & it could just be a chest infection? Or mild emphysema

???

Chest xray yesterday ... no results yet. CT Scan in about a month.

On antibiotics, anti-histamines x 2, steroids, off cigs of course. Feeling slightly better

But desperately worried.... my kids are young, me coughing is already a background noise of their childhoods... I don't think I'm strong enough to deal with this.

Also what I'm reading suggests a constant nasal drip is one of the more serious side effects even after diagnosis - chronic bronchitis? (Dr Google again)

But my oxygen saturation was 99%, can that happen when you have copd or does it mean I can have something even worse? Or could that finger test not be very precise?

Clinging to hope that this is just a chest infection but doc (who seemed very kind but young) went straight to 'very serious' and I'm also aware I've coughed a lot anytime I've smoked for years... I have often been a heavy smoker. Crying as a I type.

Please advise.