Oh, honey,
No one things badly of you for your reluctance to use it. But the thing is, oxygen is like any other DME (durable medical equipment, like a wheelchair, etc.. As a polio survivor, it took me years to get accustomed to using my power chair in public. The thing with any kind of DME though, is the realization that it helps to extend what energy you have, and things that are normally so hard can become actually enjoyable once you get past that. I do encourage you to use the O2 when you need it. It'll improve your quality of life!
Like you, I'm eating little these days because of the "fullness" feeling. Hubby's mantra is, "have you had anything to eat since (insert time here, lol) And exercise is difficult because of the old polio. I have one diaphragm partially paralyzed, so it's elevated, and the right lung doesn't expand very well. The first cardiologist who did my cath, wanted me to walk 5 miles a day. I just looked at him, lol, and thought, "Trust me, doc. That's not going to happen." And at 72, a body's metabolism isn't conducive to weight loss.
Anyway, I understand.